The 53rd Remote

IChO 2021

Japan

July 25 ~ August 2, 2021

ReportThe 53rd International Chemistry Olympiad (IChO) 2021 Japan
Organizing Committee

The 53rd Remote

IChO 2021

Japan

ReportThe 53rd International Chemistry Olympiad (IChO) 2021 Japan
Organizing Committee

RemoteThe 53rd IChO 2021 Japan
ReportPrinted on April 21, 2022 in Japan
Published by The 53rd International Chemistry Olympiad (IChO) 2021 Japan
Organizing Committee
Produced by The 53rd International Chemistry Olympiad (IChO) 2021 Japan
Secretariat Office
Edited & DTP & Printed by MITSUBA TOTAL PRINTING CO.,LTD.

This report is also uploaded on the website of The 53rd IChO 2021 Japan.
(https://www.icho2021.org/)

The 53rd IChO 2021 Japan
ReportTable of Contents
Message .............................................................................1
President of IChO 2021 Japan Committee
Chair of the 53rd IChO 2021 Japan Organizing Committee

Kohei Tamao

Overview .............................................................................4
Member of the Steering Committee
Member of the 53rd IChO 2021 Japan Organizing Committee
Vice Chair of Science Committee
Vice Chair of Executive Committee
Kanagawa University, Professor

Nobuhiro Kihara

National Team of Countries ...........................................11
Results ............................................................................. 55
Certificate and Medals ....................................................71
Memento and Gifts ..........................................................75
IChO 2021 Japan Photo Collection ..............................78
Examination ..................................................................... 83
Examination Guideline .................................................... 85
Problem English Version with Solution............................ 99

Reference : Practical Tasks .........................................177
Catalyzer .........................................................................197
IChO 2021 Japan Pre-event ....................................... 256
Committee ......................................................................258
Acknowledgments to Donations ..................................271
Special Thanks to Various Contributions ...................275

Message
Kohei Tamao
President of IChO 2021 Japan Committee
Chair of the 53rd IChO 2021 Japan Organizing Committee

The 53rd International Chemistry Olympiad, IChO 2021 Japan, was held remotely from July
25 to August 2, 2021, under the slogan “Chemistry! It’s Cool!”.
Originally, we had been preparing to hold IChO 2021 Japan at Kindai University, one of
the biggest private universities in Japan, located in the lively and modern commercial cityof Osaka in mid-west Japan, also known as the historically important birthplace of chemical
research in this country.
However, in light of the ongoing COVID-19 pandemic, we had no choice but to hold IChO
2021 remotely, following the lead of IChO 2020 Turkey last year.
This was the result of giving top priority to the safety of our young talented students andall participants, even at the expense of practical examinations and opportunities for in-person
international exchange. I would like to thank all the International Steering Committee members
led by Dr. Gábor Magyarfalvi for their enthusiastic discussion and acceptance of our decision.
The purpose of the IChO is not only to provide a venue for a test of students’ chemistry skills,
but also to foster communication among students through chemistry and to gain familiarity
with the culture of the host country. Despite being a remote competition held under thedifficult conditions presented by the COVID-19 pandemic, the question of how to effectively
implement these three elements was our biggest challenge.
The key dates were as follows:
July 25 (Sunday): Opening Ceremony
July 28 (Wednesday): Theory Examination
August 2 (Monday): Closing Ceremony
On other days, we offered various initiatives for students to create international friendships
and become familiar with Japanese culture, in addition to the challenges of the scientificcompetition. We also provided a demonstration video of the practical tasks to compensate
for the fact that the practical examinations could not be held. Virtual reality avatars for all
students were prepared to facilitate remote networking and to give greater realism to virtual
participation in the realistic Opening and Closing Ceremonies and virtual visits to sensitive
areas such as SPring-8, the world largest synchrotron radiation facility, and the restoration

Message1

site of an ancient Buddha statue to which access is normally prohibited. The IChO newsletter
Catalyzer, including these all items, was published every day for a total of 11 editions.
The good news was that we accepted 312 talented students registered from the highest-ever
85 countries and regions of the 89 to which we sent invitations. I would like to express mysincere gratitude and respect for the wonderful efforts of mentors, teachers, and all concernedin each country (in total, 520) to select talented students and set up the examination sites intheir own countries.
The theoretical examinations were held on July 28th in each country: the first started at 12:00
JST in New Zealand, the easternmost country, and the last started at 24:00 JST in the USA and
Costa Rica, the westernmost countries. The 5-hour examinations ended at 5:00 am JST on July
29. All examination sites were monitored and recorded throughout the examination via Zoom
through 100 PC monitors. It is my great pleasure to report that all theoretical examinations
were carried out in an atmosphere of justice, fairness, and trust, maintaining the spirit of
IChO, and I thank all the invigilators (in total, 183) for their earnest efforts.
In the Closing Ceremony on August 2, a list of medalists was announced: 33 Gold (top10%), 67 Silver (next 20%), 94 Bronze (next 30%) and 24 honorable mention awardees (top
10% of non-medalists). I would like to congratulate all the awardees on their very best efforts,
showcasing the talents and skills they demonstrate every day.
Now I would like to ask all the participating students to keep the following three things inmind as they reflect on this once-in-a-lifetime valuable experience.
First, they were given hope and courage to overcome difficulties through participation in
IChO 2021 Japan.
Second, the unprecedented difficulties we are still facing can only be overcome byinternational friendships and trust.
Third, I want them to remember that chemistry, the central science, is all around us. Chemistrymust therefore play a key role in finding solutions for many global challenges, including theenergy, environmental, and resource-related challenges that humanity is now facing.
I hope that IChO 2021 Japan helps to foster many talented young people who will go on toplay roles as future world leaders. While these talented students did not have the opportunity
to meet each other in person this time, I am convinced that one day they may meet eachother somewhere in the world when they go to university or graduate school. I sincerely
hope that they take the opportunities given to them as participants in IChO 2021 to createstrong networks of international friendship, with the slogan “Chemistry! It’s Cool!” as theirwatchword.
Finally, I would like to thank IUPAC, the Ministry of Education, Sports, Science andTechnology (MEXT Japan) and the Japan Science and Technology Agency (JST) for their2

The 53rd IChO 2021 Japanmeaningful support, and the more than 180 chemical companies and trading companies inJapan as our sponsors for their substantial financial assistance, as well as numerous personal
donations.
My special thanks are also due to all the members of the Japan Committee and Organizing
Committee for IChO 2021 Japan, as well as our secretariat and KNT Corporate Business Co.,
Ltd. Without their remarkable support and endeavors, this remote IChO 2021 Japan would
not be possible.

Message3

Overview
The IChO program is intended to stimulate students’ interest in chemistry through solving
creative chemical problems that are both practical and theoretical. In a usual IChO, theparticipating students are tested on their chemistry knowledge and skills in a five-hourlaboratory practical examination and a five-hour written theoretical examination. It also
aims to promote international contacts in chemistry, friendships between young chemists ofdifferent nationalities, cooperation among pupils, and exchange of scientific experiences inchemistry.
At 47th IChO 2015 in Baku, Azerbaijan, Japan was invited to hold the 53rd IChO in 2021.
It was originally planned to follow the 2020 Olympic and Paralympic Games in Tokyo. We
anticipated that popular interest in chemistry would be enhanced by a scientific Olympiad
being held after the excitement of a sporting Olympiad.
When we heard the first reports of COVID-19 early in 2020, it appeared to be a minor
concern. Despite the virus being thought of as causing a new kind of cold, we knew that thecommon cold is inactive in summer when the IChO was to be held. However, shortly after the
pandemic spread across the globe, it became evident that COVID-19 was active in summer,
too. The 2020 Olympics and Paralympics were postponed for one year, and the 52nd IChO
2020 in Turkey was held remotely, because the university venue could not be used for an inperson event during the period scheduled for the IChO.
The IChO is composed of three key elements:(1) Examination
Chemistry is an experiment-based science, with every theory coming out of the laboratory.
Therefore, both theoretical and practical examinations play important roles in the IChO.
(2) Communication
Talented students from all over the world come together to take part in the IChO.
Conversation, cooperation, and communication with each other provide a great opportunity
for promising youngsters to enjoy international experiences and to make friends with otherparticipants via their common interest, chemistry.
(3) Culture
The venue chosen for the 53rd IChO 2021 Japan, the Kansai area, is 500 km from Tokyoand was the ancient capital where the first government of Japan was established 2681 years
ago (according to Japanese legend). Several places were to be visited, including not only very
old temples but also state-of-the-art scientific institutes.

4

The 53rd IChO 2021 JapanIn the middle of January 2021, the Organizing Committee (OC) of the 53rd IChO 2021
Japan met with the Steering Committee (SC) of the IChO via Zoom. We discussed two
proposals: for an in-person IChO and a remote IChO. Unfortunately, it was already clear that
all the elements of the IChO described above could not be included in an in-person IChO
during the COVID-19 pandemic, due to difficulties in immigration control and the need forsocial distancing.
The first priority of any IChO is, of course, the safety of all participants. After the meetingwith the SC, the OC finally decided to hold the 53rd IChO 2021 Japan as a remote event. At
the end of February, when we had our second meeting with the SC, the holding of a remote
IChO was approved.
In this remote IChO, the competition only involved theoretical problems, and the students
attended the examination from their own countries. Most of the elements essential to the IChO
would be lost in the remote IChO, which was very disappointing.
Even in a remote format, however, the important features of IChO must be maintained asmuch as possible. The participating students must have extraordinary experiences. Therefore,
the OC incorporated several activities and communication tools into the 53rd IChO 2021
Japan to cover these important features:(1) Examination
In order to reinforce the importance of laboratory work, the practical tasks prepared forthe 53rd IChO 2021 Japan were made open, despite not being officially approved by theInternational Jury meeting for the 53rd IChO 2021 Japan. The OC prepared videos in which
all tasks were demonstrated with explanations and published the videos as one of the activities
during the 53rd IChO 2021 Japan.
The OC will be delighted if those who are inspired by the demonstrations prepare andsubmit their original videos in which they attempt the practical tasks and discussions. Reportson the tasks will also be highly welcome.
(2) Communication
OC prepared a virtual reality (VR) space for communication. When participants accessed
the VR space, their avatars were created. Everyone could participate in events and activities
via their avatars. In the VR space, there were venues in which avatars could enjoy close
conversations, cooperation, and communication with others.
(3) Culture
IChO participants were offered virtual visits to several locations. Some of these had beenplanned for the in-person IChO: Nara City, Osaka City, Kyoto City, and Himeji Castle.
However, the OC added some that are very interesting to experience but not suitable for inperson visits due to hazards, sensitivity, space limitations, or language difficulties. SPring-8,

Overview5

a large synchrotron radiation facility that delivers the most powerful synchrotron radiation
currently available, is one of the most interesting places in the Kansai area for the participating
students of the IChO in particular. However, it is very difficult to visit SPring-8 as an activity
in the IChO due to space limitations inside SPring-8 and the sensitivity of its advanced
instruments. A workshop for preserving cultural assets, for example, repairing an image of
Buddha, is another interesting place where modern chemistry is applied to very old subjects,
although it is again very difficult to physically visit such a workshop because of the sensitive
work, space limitations, and language difficulties. In the 53rd remote IChO, the participants
virtually visited these highly restricted locations to experience more interesting cultural tours
than would otherwise be possible.
The preparation of the problems started at April 24, 2018 in the first meeting of Science
Committee of OC. After several intensive discussions and meetings, nine theoretical problems
and three practical tasks were selected, and were brushed up to high quality problems. To
complement these problems, thirty-one theoretical problems and seven practical tasks wereprepared to be issued as the Preparatory Problems at February 1, 2021.
The opening ceremony started at 15:00 JST on July 25, 2021. The participants of the 53rd
IChO 2021 Japan could access the ceremony via either the VR space or the usual video
streaming. Over 200 participants entered the VR space to enjoy the realistic ceremony.
The first version of the theoretical problems was published at 21:00 JST on July 25. Itshould be noted that 21:00 JST is the almost the only time window to permit cooperation onthat day all over the world: 21:00 JST is 24:00 for the easternmost country, New Zealand,and 9:00 for the westernmost country, Costa Rica. Therefore, most of the programs werescheduled at 21:00 JST during the 53rd IChO 2021 Japan.
The Science Committee of OC sought comments on the problems from mentors, revised
the problems according to the comments, then proposed a second version of the problems
for finalization to the international Jury meeting, the body that decides matters regarding
the IChO that bind both participants and organizers. The Jury meeting started at 21:00 JST
on July 26 and finished around 2:00 JST on July 27. The Science Committee of OC revised
the problems according to the decisions of the Jury meeting and published the official final
version at 9:00 JST on July 27. Next, the mentors started to translate the official English
version into the individual local languages for their students. All delegations finished theirtranslations by 9:00 JST on July 28.
It should be noted that 60 hours elapsed from the publication of the first version of the
problems to the deadline for translation. Of course, contact between mentors and students
after the publication of the problems was clearly prohibited in the competition guidelines. If
a mentor wanted to cheat, for example, passing on the problems and solutions to his or her

6

The 53rd IChO 2021 Japanstudents, we could not prevent it. However, the OC trusted in the professionalism and the
pride of mentors. If a mentor had said to their students, “Hey, I’ll tell you the problems andsolutions, then you’ll all get gold medals,” they would lose the respect of their students. As
expected, there were no suspicious results in the scores obtained by participating students,
confirming that the IChO community is strong and ethically healthy.
The translated versions of the problems were made available to the invigilators at 9:00
JST on July 28. The invigilators downloaded and printed out the problems for students by
the starting time of the examination. The invigilators are a crucial component of the remoteexamination. The OC asked country delegations to appoint invigilators who are independentof the mentors, have no relationship with students and have no other activity in the 53rd IChO
2021 Japan. Invigilators were to be socially well-established persons such as school principals
and should not be a parent or a relative of a student. For the same reason, the examination
location should be a public place such as a school, and the OC requested that each country
choose a single location per a country.
Unfortunately, restrictions on movement were very severe in some countries during theperiod for the 53rd IChO 2021 Japan. Further, some students had to quarantine because theirclose relatives were infected by COVID-19. In such urgent circumstances, the OC allowed
these students to take the examination in their homes, invigilated by their parents. The relevantdelegations were asked to guarantee the fairness of the examination, and all delegations
worked hard to make the students’ homes suitable as examination locations.
A total of 309 students took the examination, while three students were absent. All
examination locations were inspected beforehand via Zoom and were monitored and recorded
throughout the examination via Zoom.
The earliest examination started at 12:00 JST on July 28 in New Zealand, the easternmost
country, and the last examination started at 24:00 JST in USA and Costa Rica, the westernmost
country. The examination time was 5 hours. Participating students were not allowed to use
any communication devices or computers during the period 19:00 to 24:00 JST to avoid any
ill-intentioned communication via the Internet or social media. All these requirements were
controlled by the invigilators.
After the examination, the invigilators sorted the answer sheets by page numbers, scanned
them to prepare PDF files for each student, and submitted them to the OC. After all answer
sheets were received, the Science Committee of OC started marking at 9:00 JST on July 29.
In the same time, a pdf file with the answer and the marking scheme was published to all
mentors, and mentors also started marking in their own countries. At 23:00 JST on July 29,
we published our marking, and started receiving the request of arbitration from mentors till
20:00 JST on July 30.

Overview

7

The arbitration was carried out from 9:00 JST for easternmost countries to 24:00 JST forwesternmost countries on July 31. The final results after reflection of all results of arbitration
were sent to each country at 6:00 JST on August 1. It was announced to the mentors that any
query for the final results should be sent to the Science Committee of OC within 6 hours,
although no argument came to OC. Thus, the scores of all students were fixed and finalized at
12:00 JST on August 1, and the medals were allocated according to the regulation of IChO.
The students were awarded in the closing ceremony at 21:00 JST, on August 2, which washeld also in the VR space and later published as a streaming video. Even after the closing
ceremony, the participants could still enjoy virtual tours in the VR space.
The 53rd IChO 2021 Japan was financially supported by IUPAC, the American Chemical
Society and Chinese Chemical Society in Taipei. Theses supports were used to subsidize
participation fees for some countries that were facing economic difficulties. This year, there
were several countries experiencing economic difficulties due to the COVID-19 pandemic.
The 53rd IChO 2021 Japan was totally managed by Zoom and Oly-Exam softwares. Zoom
was used for the international discussion, e.g., Jury meeting and arbitration, and monitoring
the examination. Oly-Exam was used for the preparation and translation of the examination
problems and grading. On-time communication with mentors was carried out with mail andTelegram software.
After several events over the period of 11 days, the 53rd IChO 2021 Japan was successfullycompleted. We wish to congratulate all participating students. Some received medals, andsome did not. However, they all tried their best to tackle the same chemical problems. Whenthese youngsters meet again as the leaders in the field of chemistry, they will talk about thedays of the 53rd IChO 2021 Japan. We will be deeply honored if the 53rd IChO 2021 Japan
becomes one of the career milestones marked by the excellent chemists of the future.

Nobuhiro Kihara
Member of the Steering Committee
Member of the 53rd IChO 2021 Japan Organizing Committee
Vice Chair of Science Committee
Vice Chair of Executive Committee
Kanagawa University, Professor

8

The 53rd IChO 2021 Japan

The 53rd IChO 2021 Japan
July 25 〜 August 2, 2021

Event Period

Main hostThe 53rd International Chemistry Olympiad (IChO) 2021 Japan Organizing Committee

Co-hostJapan Science and Technology Agency (JST)Endorsing Institution

Ministry of Education, Culture, Sports, Science and Technology (MEXT)
Ministry of Economy, Trade and Industry (METI)
Osaka Prefecture Board of Education

Participating countries/regions 79＋5 Observer countries
Number of participants 709
Students 312(Number of examinees 309)
Mentors 160
Observers 51
Guest 1
Invigilators 185

Schedule
Date

JST Time(UTC+9)Jul 22, Thu

21:00

Jul 23, Fri

21:00

Jul 24, Sat

0:00

Student

Mentor/Observers

Invigilator

Jul 26, Mon

15:00

Mock exam

Training of Oly-Exam(Zoom)
Opening
Ceremony

Opening Ceremony

21:00

Receipt of the problem
for review (Oly-Exam)

9:00

Deadline of feedback(Oly-Exam)

21:00

Jury meeting (Zoom)

Jul 27, Tue

9:00

Receipt of the authorized
problem for translationand submission (OlyExam)

Jul 28, Wed

9:00

Deadline of translation

14:00
↓
29:00

Examination(5 h)
Asia →
Europe →America

23:00

Mock discussion

Mock discussion

Opening Ceremony

Opening Ceremony
Publication of the
problem (Oly-Exam)

Jury meeting (Zoom)

Jury meeting (Zoom)
Publication of the
final version of official
problem (Oly-Exam)
Information of erratum(Zoom)

Receipt of the problem
to print out (Oly-Exam)
Observation of every
examination (Zoom/
video)
Receipt of all solutions(Oly-Exam) and reports(mail)SC meeting (Zoom)

9:00
9:00

Opening Ceremony

Submission of thesolutions (Oly-Exam)within 2 hours after theend of the examination

21:30
Jul 29, Thu

Organizer

Training of Oly-Exam(Zoom)

21:00
Jul 25, Sun

SC

Receipt of the answer
with grading scheme(Oly-Exam)
SPring-8
virtual tour

Distribution of theanswer with grading
scheme (Oly-Exam)

SPring-8 virtual tour
Receipt of scores from
Organizer (Oly-Exam)
Request for arbitration(Oly-Exam)

Publication of scores(Oly-Exam)

9

Date

JST Time(UTC+9)Jul 30, Fri

9:00

Student

Mentor/Observers

Video of
Practical Task

Video of Practical Task

20:00

Deadline of arbitration
request

21:00

Jury meeting (Zoom)

Jul 31, Sat

9:00

Aug 1, Sun

6:00
9:00

Video ofpreserving
cultural assets

Virtual visit
for Himeji
Catle, Osaka,
Kyoto

12:00
Aug 2, Mon

21:00

Invigilator

SC

Jury meeting (Zoom)
SC meeting (Zoom)

Organizer

Jury meeting (Zoom)

Arbitration (Zoom)
Asia → Europe →America

Arbitration (Zoom)

Receipt of final results(mail)

Report of final points(mail)

Virtual visit for Himeji
Catle, Osaka, Kyoto
Deadline of argument

Closing
Ceremony

Profit and loss statement

Closing Ceremony

Closing Ceremony

Closing Ceremony

Closing Ceremony

2019.4～2022.3

income1 USD → 114 Yen
Account

detailDollarDonation income

1,941,560

Subsidies from the country

1,604,986

Participation fee income

85,865Interest income

168

Miscellaneous income

414

Total amount

3,632,993

Donation income

DollarDonations from ACS,IUPAC,CSLT
Donations from companies
Donations from individuals

Total amount

6,217
1,915,877
19,465
1,941,560

ACS(American Chemical Society)
IUPAC(International Union of Pure and Applied Chemistry)
CSLT(Chemical Society Located in Taipei)

cost
Account
labor cost
Payroll taxes expensedetailDollar494,258

Expenses directly related to the 53rd IChO 2021 Japan 2021.7.25～8.2

3,786

Welfare expenses

344

Outsourcing cost

2,075,278

Dollar

VR-AVATER production cost

666,349

Video production cost

511,650

labor cost

90,788

Conference expenses

9,548

Ceremony production cost

53,070Traveling expense

88,955accommodation charge

68,068

Postage expense

12,163

Meeting room rental fee

527,904

Supplies expenses

172,710cost of a meal

9,491

Office maintenance and management fees

88,272

Courier fee and others

4,439

PC rental fee for monitoring, etc.

31,546

Commission paid

Member dues

2,370

Medals and other souvenirs

95,750

Lease expenses

31,449shipping charges

81,013

Taxes and dues
Compensation paid
Donations expense

114

932
4,075
3,881

administrative expenses

193,431

Participation fee

17,222Printing costs

792

Miscellaneous expenses

114

Relocation fee

309

Total amount

3,200,003

10

The 53rd IChO 2021 Japan

part-time job offer
Total amount

12,934
2,153,002

National Team ofCountries

Armenia
Armenia

Hayk Aghekyan

Student

Leonid Asatryan

Tigran Harutyunyan

Sevada Nersisyan

Head Mentor
Andranik Davinyan

MentorArmen Galstyan

Invigilator

Artyom Petrosyan

Australia
Australia

Oscar Dong

Student

Austin Lin

Vincent Ng

Keith Wong

Head Mentor
Mackenzie Shaw

MentorAmy ZhouInvigilator

Samuel Alsop / Yao-Hua Helen Chang / Chris Choon Ng / Carol Zhang

National Team of Countries

13

Austria
Austria

Student

Paul Johann Dorfer

Lukas Rost

Michael Schembera

Maciej Swiatek

Head Mentor
Georg Schellander

MentorMathias Scherl

ObserverFelix Eder / Florian Kluibenschedl

Invigilator

Wolfgang Faber / Paul Glanzer

Azerbaijan
Azerbaijan

Salman Huseynov

Student

Mahsati Piriyeva

Nariman Shirinli

Head Mentor
Igrar Nazarov

MentorMilana Agayeva

Invigilator

Ali Aliyev / Bezlepkina Veronika

14

The 53rd IChO 2021 Japan

Khanim Yagublu

Bangladesh
Bangladesh

Tawhid Muhammad
MubashwirStudent

Safwan Sakib

Mahin Kamal
Sawdager

Khalid Hasan Tuhin

Head Mentor
Md Wahab Khan

MentorMohammad Shoeb

ObserverMd. Abdul Jabbar / Md. Nurnabi

Invigilator

Md. Aminul Haque / N. K. M Akber Hossain / Md. Iqbal Rouf Mamun / Chanchal Kumar Roy

BelarusBelarusUladzislau Hlatankou

Student

Kiryl Maroz

Angelina Rogatch

Alina Tumashyk

Head Mentor
Viktar N. Khvalyuk

MentorDenis G. Shklyaruck

Invigilator

Natallia Babaryka / Ekaterina Pavlyuchkova

National Team of Countries

15

Belgium
Belgium

Louis PecheurStudent

Lukas Schieble

Jef H. K. Van Eester

Daan Roger Stan
Vanhaecke

Head Mentor
Hans Vanhoe

MentorSylvestre Dammicco

Invigilator

Gilliard Laurane / Cedric Malherbe

BrazilBrazilCassia Caroline
Aguiar da Ponte

Student

Vinicius da Silveira
Lanza Avelar

Marina Malta Nogueira

Head Mentor

Lucas Carvalho Veloso Rodrigues

Mentor

Joao Paulo Ataide Martins

ObserverSamuel Anderson Alves Sousa

Invigilator

Sergio Maia Melo / Nagila Maria Ponte Silva Ricardo

16

The 53rd IChO 2021 Japan

Hana Gabriela
Albuquerque Sousa

Bulgaria
Bulgaria

Teodor Svilenov
Maslyankov

Student

Georgi Neliyanov
Nedyalkov

Pavel Atanasov Nikolov

Samuil Vladimirov
Petkov

Head Mentor

Donka Nikolova Tasheva

MentorPenka Vasileva Tsanova

Invigilator

Nikola Tomov Burdzhiev / Plamen Danchev Kolev

CanadaCanadaAndrei Banica

Student

Andy Cai

Michael Li

Terry Wang

Head Mentor
Guillaume Bussiere

MentorJennifer Pitt-Lainsbury

Invigilator

Yi (Louise) Lu / Yaoguang Luo / Aleksandra Milicevic / Lisa Stepaniants

National Team of Countries

17ChinaChina

Xinyu Cai

Student

Zhangyi Huang

Shu YangBangsen Zhao

Head Mentor
Yingxia Wang

MentorPing Lyu

ObserverQiaohong He / Zhengjie He / Kai Li / Huaping Xu

Invigilator

Qi Chen / Yinxia Yuan

ChineseChineseTaipei
Taipei

Bo-An ChenStudent

Hsuan-Ting Lin

Chun-Cheng Ting

Head Mentor
Way-Zen Lee

MentorCheng-Huang Lin

Observer

Yu-Tzu Li / Hsiao-Hua Yu

Invigilator

I-Ren Lee / Ming-Kang Tsai18

The 53rd IChO 2021 Japan

Rui-Xi Wang

CostaCostaRica
Rica

Olivia Sojourner Dixon

Student

Ignacio Herrera
GamboaFanny Mariana Solís
González

Head Mentor

José Roberto Vega-Baudrit

MentorWendy Villalobos González

Invigilator

Mario Villalobos Forbes / Andrea Rivera

Croatia
Croatia

Jasmin Jasarevic

Student

Olga Jerkovic Peric

Fran Miletic

Marko Preocanin

Head Mentor
Branka Zorc

MentorBranimir Bertoša

Invigilator

Tin Klacic / Darko Vušak

National Team of Countries

19

Cyprus
CyprusChristiana Kosta

Student

Giorgos
Papachristodoulou

Stylianos Tamasios

Jessica Thackeray

Head Mentor

Stella Ioannou Loucaidou

MentorGeorgios Miliotis

Invigilator

Marios Christodoulou / Georgia Ioannou

Czech
CzechRepublic
Republic

Tomáš Heger

Student

Filip Hůlek

Marek Pavlica

Head Mentor
Petr Holzhauser

MentorJiri Ledvinka / Petra Ménová / Lukas Tomanik

Invigilator
Josef Tomeček

20

The 53rd IChO 2021 Japan

Jakub Sochor

Denmark
Denmark

Student

Lin Bigom-Eriksen

Michael Estes

Melanie Muntz

Theodor Malte Novrup
Redvall

Head Mentor

Kurt Bjoenager Nielsen

MentorPia Nielsen

Invigilator

Susanne Lis Mossin / Michael Munck

ElElSalvador
SalvadorFredi Manuel Barraza
Hernandez

Student

Luis Ronaldo Chavez
Escamilla

Emily Alejandra
Crespin Guerra

Brenda Nicole Juarez
Marroquín

Head Mentor

Johnny Jose Marquez

MentorMarvin Alberto Ramirez Alas

Invigilator

Edwin Bladimir Bonilla Ascencio / Rodrigo Ernesto Robles Burgos / Bryan Manuel Salguero Cardoza
Alejandro Adrián Ayala Escamilla

National Team of Countries

21Estonia
Estonia

Aleksandr Beditski

Student

Andrei Kornijenko

Liis Siigur

Siim Tiivel

Head Mentor
Ida Rahu

MentorSiim Kaukver

Invigilator
Jörgen Metsik

FinlandFinland

Aku Hertell

Student

Henri Kärpijoki

Otto Keronen

Head Mentor
Kjell Knapas

MentorMiia Mäntymäki

ObserverJuulia Talvitie

Invigilator

Mikko Kaipio / Leevi Pesonen

22

The 53rd IChO 2021 Japan

Samuel KlaverFrance
FranceAlexandre Bloquel

Student

Théodore Halley

Théo Mignen

Ruben Tapia

Head Mentor
Clément Guibert

MentorAlix Lenormand

Invigilator

Aurélien Moncomble

Georgia
Georgia

Nino Abesadze

Student

Lizi Darchia

Ioane Kapanadze

Ketevan Peranidze

Head Mentor

Elizbar Elizbarashvili

MentorVakhtang Kurtskhalia

ObserverTinatin Buthkhuzi / Sophiko Phatsatsia

Invigilator

Tamar Bokuchava / Mariam Ghachava / Gia Khatisashvili / Ekaterine Mikautadze

National Team of Countries

23Germany
Germany

Johann Sora Blakytny

Student

Tim Bastian Enders

Fynn Lasse Noah
Kessels

Linus Albert Schwarz

Head Mentor
Frank Witte

MentorFelix Strieth-Kalthoff

ObserverMaximilian Fellert

Invigilator

Jan Hendrik Frenzel / Philipp Gremler / Uta Purgahn

GreeceGreeceAthanasios Feidakis

Student

Ioannis Karageorgiou

Vasileios
Papastamopoulos

Head Mentor

Nikolas Psaroudakis

MentorGeorgios Melidoneas

Invigilator

Alexandros Terzopoulos

24

The 53rd IChO 2021 Japan

Dimitrios Stylianakis

Hungary
Hungary

István Babcsányi

Student

Dávid Benkő

Benedek Sajósi

Lucio Saracco

Head Mentor
Gábor Magyarfalvi

MentorSzilárd Varga

ObserverKatalin Zih-Perenyi

Invigilator

Gyorgy Koczan

Iceland
Iceland

Dagur Bjorn
Benediktsson

Student

Telma Jeanne
Bonthonneau

Isak Hugi Einarsson

Daniel Heidar Jack

Head Mentor

Katrin Lilja Sigurdardottir

MentorMar Bjorgvinsson

Invigilator
Rafn Rafnsson

National Team of Countries

25

IndiaIndia

Student

Mahit Rajesh
Gadhiwala

Adarsh Reddy Madur

Dhananjay Raman

Rishit Singla

Head Mentor
Ankush Gupta

MentorNandita Madhavan

ObserverDimple Dutta

Invigilator

Rajesh Chandrakant Gadhiwala / Rupa Reddy Madur / Swapna Mahesh Narvekar / Praveen Pathak /Shirish Rajan Pathare / Lalitha Raman / Harita Pankajkumar Raval / Indrani Das Sen / Dinesh Kumar Singla

Indonesia
Indonesia

Kevin Lius Bong

Student

Faatih Regind Qashash
Roman

Nathanael Reza Putra
Widjaja

Hanif Muhammad
ZhafranHead Mentor

Deana Wahyuningrum

MentorFainan Failamani

ObserverIrma Mulyani

Invigilator

Azis Adharis / Damar Nurwahyu Bima / Arie Hardian / Fatiha Khairunnisa

26

The 53rd IChO 2021 Japan

Iran
Iran

Student

Mahyar Afshinmehr

Mahbod Alian Fini

Seyed Mohammad
Hossein Barakati

Ehsan Naderi Donig

Head Mentor
Seifollah Jalili

MentorEbrahim Kianmehr

Invigilator

Bahram Madadi / Shahram Seidi

Ireland
Ireland

Oscar Eric Moran
DespardStudent

Aoife Mary Morris

Oisín Colm
Ó Feinneadha

Tong Wu

Head Mentor
Carl Poree

MentorBrian Martin Murphy

ObserverElizabeth Sarah Gilchrist / John Daniel O’Donoghue

Invigilator

Adrian Sanz Arjona / Susannah Calvert / Aine Coogan / Annie Regan

National Team of Countries

27

IsraelIsraelStudent

Nir Cohen

Neta Eiger

Tal Sason

Itamar Steinitz

Head Mentor
Izana Nigel

MentorAssaf Mauda

ObserverZeev Groos

Invigilator
Maria Lavi

Japan

Student

Haruhi Isse

Yuya Koike

Kohei Nishiura

Head Mentor
Akira Nagasawa

MentorTsuyoshi Yamaguchi

Observer

Asao Nakamura / Toru Shimada

Guest

Takuji Hirose

Invigilator

Tomohiro Iwai / Hiroyuki Okura / Noriyuki Yonezawa

28

The 53rd IChO 2021 Japan

Takahiro TakemotoKazakhstan
Kazakhstan

Sanzhar Bissenali

Student

Khaidar Kairbek

Madiyar Kassymaly

Aigerim Turuspekova

Head Mentor
Yernur Tolep

MentorAnton Morgunov

Invigilator

Yerbolat Ablemetov / Zharlagapova Zere

Korea
Korea

Seung Jae Kang

Student

Seoyeon Kim

Myeongjin ShinHee Seong Yoon

Head Mentor
Bongjin Moon

MentorSung Ik Yang

Observer

Hyuk Kang / Myung Hwan Park

Invigilator

Myeong-Sook Kim / Yelim Kim

National Team of Countries

29

Kyrgyzstan
Kyrgyzstan

Kamil Mambetov

Student

Nadezhda Ondrina

Ivan Reshetnikov

Azamat Salamatov

Head Mentor
Bakut Borkoev

MentorKalipa Salieva

Invigilator

Dooronbek Mametov / Sharshenali Saitkulov

LatviaLatviaDaniils Kargins

StudentDžonatans Miks
Melgalvis

Vladislavs Tiščenko

Head Mentor
Nauris Narvaišs

MentorRitums Cepītis

Invigilator

Kristine Zadvinska

30

The 53rd IChO 2021 Japan

Edvards Jānis Treijs

Lithuania
Lithuania

Tadas Danilevicius

Student

Povilas Dapsys

Laimis Jurkenas

Simonas Melaika

Head Mentor
Rimantas Raudonis

MentorLukas Steinys

Invigilator

Vytautas Kavaliauskas / Agne Kizalaite

Luxembourg
Luxembourg

Laurent Bommertz

Student

Rafael Dux

Jean-Marc Furlano

Raphaël Menasce

Head Mentor
Sam Hoffmann

MentorSven Linster

Invigilator
Claude Kiefer

National Team of Countries

31

Malaysia
Malaysia

Bernie Lim Wei Yuan

Student

Shawn Vernon Wong
Siang RayLim Xu Yao

Wong Yi Yang

Head Mentor

Noorsaadah Abd Rahman

Mentor

Sharifuddin Md Zain

Invigilator

Jahari Jainal / Lee Lay Peng / Goh Boon Swee / Mary Wong

MexicoMexicoJorge García-Ponce

Student

Gerardo Emiliano
Gutierrez-Alvarez

Emmanuel
Sotomea-Renova

Head Mentor

Carlos M Castro-Acuna

MentorDavid Octavio Corona-Martinez

Invigilator

Hector García-Ortega / Gabriel Palacios-Huerta

32

The 53rd IChO 2021 Japan

Emilio Alonso
Venegas-HernandezMoldova
Moldova

Adelina Andrei

Student

Maxim
Cojocari-Goncear

Valerian Mocreac

Tatiana Sviriniuc

Head Mentor
Ion Bulimestru

MentorVasile Graur

Invigilator

Stanislav Ciubotaru / Diana Cojocaru

Mongolia
Mongolia

Irmuun Altankhuyag

Student

Gerel Bayarmagnai

Bumchin Dolgormaa

Temujin Orkhon

Head Mentor

Otgondemberel Galaaraidii

MentorNyamgerel Choijilsuren

ObserverMunkhjargal Burenjargal / Battugs Davaasambuu

Invigilator

Altanzul Altangerel / Saruul Idesh

National Team of Countries

33

Montenegro
Montenegro

Danijel Aleksic

Student

Iva Djurickovic

Ksenija Tadic

Milica Zizic

Head Mentor
Miljan Bigovic

MentorBojana Ostojic

Invigilator

Momir Radulovic / Ivana Vukcevic

Netherlands
Netherlands

Sebastian Jacob Krikke

Student

Mitchell Rikken

Jochem van den Broek

Head Mentor
Emiel de Kleijn

MentorKees Beers

Invigilator

Martin Groeneveld / Dick Hennink / Marijn Jonker

34

The 53rd IChO 2021 JapanMax Rudolf Antonius
Karel van Hest

New
NewZealand
Zealand

Abhinav Chawla

Student

Daniel Jiyoun Jang

Mason Minghan Liu

Sam Wuji Zhuang

Head Mentor

Duncan J McGillivray

MentorSheila Woodgate

Invigilator

Jan Giffney / Stephen McCracken / Andrew Rogers

Nigeria
Nigeria

Joseph Eghenevwegba
Ikuru

Student

Winston Ukpong

Ifeanyichukwu
Valentine Umeanyika

Head Mentor
Chinenye Nna Orji

MentorAishat Yetunde Abdulkareem

Invigilator

Ugochukwu David Uche

National Team of Countries

35

NorthMacedonia
North
Macedonia

Student

Anja Spasovska

Jan Stojanovski

Darko Stojchev

Mihail Trajkov

Head Mentor
Miha Bukleski

MentorNatasha Ristovska

Invigilator
Leon Stojanov

NorwayNorwayAbdur-Raheem Idowu

Student

Tina Kalleson

Joachim Julian
Klaussen

Head Mentor

Hans-Petter Hersleth

MentorKristian VestliInvigilator

Bjørn Dalhus / Henrik Hovde Sønsteby

36

The 53rd IChO 2021 Japan

Simen Mannsåker

Oman
Oman

Student

Lujaina Al Badi

Arwa Al Hashimi

Abdullah Al-Azri

Maryam Al-Hatmi

Head Mentor
Mohamed Alnaabi

MentorSaid Al Ghawi

Invigilator

Fatma Al Badi / Nasser Al Mushaifri / Sultan Al Rahbi / Mohsin Al Riyami

Pakistan
Pakistan

Muhammad Ismail

Student

Ayesha Junaid

Rameesha Khursheed

Muhammad Yahya

Head Mentor
Khan M. Khalid

MentorMuhammad Raza Shah

Invigilator

Arslan Ali / Muhammad Imran Malik / Syed Muhammad Saad

National Team of Countries

37

Philippines
Philippines

Nathan Wayne F.
AristonStudent

Ron Angelo A. Gelacio

Aames Juriel B.
Morales

Kristoff John F. Padilla

Head Mentor
Jose M. Andaya

MentorFaith Marie Goli Lagua

Invigilator

Aimee Fontanilla Ariston / Kenneth Arnyl Diaz / Maria Ana Atienza Gelacio /Merlyn Beladas Morales / Raymond Rosalejos Padilla

PolandPolandJakub Krzysztof
Kwiatkowski

Student

Michal Piotr Lipiec

Bruno Andrzej Skoczen

Head Mentor
Marek Orlik

MentorAleksandra Misicka-Kesik

Observer

Piotr Kwiatkowski

Invigilator
Ewa Pobozy

38

The 53rd IChO 2021 Japan

Adam Szymon
Sukiennik

Portugal
PortugalJoão Pedro Bonito
Caldeira

Student

Mariana Vilela Marta
Rio Costa

Tiago Miguel Gomesde Sousa

Beatriz Crisóstomo
Valério Figueiredo

Head Mentor

Vasco Figueiredo Batista

MentorJoão Miguel Pimenta Pereira

Invigilator

Diana Cláudia Gouveia Alves Pinto / Carlos Fábio Magalhães da Silva

Qatar
Qatar

Nihit Agarwal

Student

Sara Fahed Al ali
AlahmadAsmahan Abdulaziz
Al-Kuwari

Sushanthi Anandaraja

Head Mentor

Lamyah Yousef Al-Hayki

MentorRabab Farouk Awad

ObserverEmad Abdel Rehem Alsaifi / Sherif Abdel Hamid Elhefnawi

Invigilator

Sahar Mohammed Omar / Wafaa Gafer Othman

National Team of Countries

39Romania
Romania

Mircea Raul Bodrogean

Student

Alexandru Catalin
Dianu

Stefan Dimitriu

Tudor Lile

Head Mentor
Marius Andruh

MentorMihaela Matache

Invigilator

Adrian Apostol / Anca Paun / Codruta Popescu

RussianFederation
RussianFederation

Student

Timofey A. Charkin

Aleksandr E. Trofimov

Andrei S. Tyrin

Head Mentor
Vadim V. Eremin

MentorAlexander S. Belov

ObserverAlexander K. Gladilin / Leonid V. Romashov

Invigilator

Sergey I. Kargov

40

The 53rd IChO 2021 Japan

Georgii M. Zhomin

Saudi
SaudiArabia
ArabiaMohammad Solaiman
AlHadlaq

Student

Mohammad Rashed
AlHudaithi

Abdulaziz
Abdulrahman AlJuaid

Saeed Sultan Baghdadi

Head Mentor

Reem Sadeq AlMohammed

MentorAbdullah Jassim AlAbdulghani

ObserverWaed Zouhir AlKayali / Bader Mohammed AlMajrathi

Invigilator

Nasser Abdullah AlObaid

SerbiaSerbiaDimitrije Gligorovski

Student

Jovan Marković

Lazar Savić

Nevena Stojković

Head Mentor
Dušan Sladić

MentorNiko Radulović

Invigilator

Irena Novaković / Vidak Raičević

National Team of Countries

41

Singapore
Singapore

Cheng Jun, Nicholas
GohStudent

Bernard Tze Wei Kwee

Alphonsus Yu Xiang
Neo

Chen Yizhou

Head Mentor
Wee Boon Tan

MentorHoang Truong Giang

ObserverKailun You

Invigilator

Stephanie Jee / Yih Check Wong

Slovakia
Slovakia

Patrik Fábrik

Student

Samuel Kolesár

Ján Plachý

Head Mentor
Martin Putala

MentorJela Nociarová

Invigilator

Samuel Andrejčák

42

The 53rd IChO 2021 Japan

Matúš Tomčo

Slovenia
Slovenia

Jernej Birk

Student

Simon Bukovšek

Vid Kavčič

Patrik Žnidaršič

Head Mentor
Andrej Godec

MentorBerta Košmrlj

Invigilator

Miha Lukšič / Aljoša Seljak

South
AfricaSouth
AfricaMohammed Tanweer
Alli

Student

Erkam Cihan Caglak

Muhammad Mahdi da
Costa

Abdul-Baasit Salie

Head Mentor
Ajay Bissessur

MentorBice Martincigh

Invigilator

Dalaal Abrahams / Ugur Hulusi Patli

National Team of Countries

43

Sri
SriLanka
Lanka

Achira Hansindu
Kelambi Arachchige

Student

Dinithi Shalika
Madhubhashini

Nadun Naveendra
Rajapaksha

Manujaya Praveen
Wijesinghe

Head Mentor

Chinthaka Nadun Ratnaweera

MentorIreshika Chathurani de Silva

Invigilator

Hasantha Abayrathna / Sameera Ranmal Gunatilaka / Dulshani Kandambi / Upeksha Welikala

SwedenSwedenElsa Bitzén

Student

Erik Bryland

Leopold Kall

Head Mentor
Johanna Rogvall

MentorErik Sundén

ObserverCecilia Stenberg

Invigilator

Mona Koder Hamid / Mikael Landgren / Tobias Sparrman

44

The 53rd IChO 2021 Japan

Yangyi Qi

Switzerland
Switzerland

Antoine Robin Chèvre

Student

Jessica Rebekka
Kurmann

Sandro Pfammatter

Head Mentor

Anastasia
Aleksandrovna
Sandamirskaya

Mario Michele Oreste De Capitani

Mentor

Maurice Cosandey

ObserverLinda Katharina Sonderegger / Silena Wegmann / Patrik Oliver Willi

Invigilator

Gunnar Jeschke / Richard Walter

Syria
Syria

Anas Abbas

Student

Maha Ali

Ahmad Thaer AterAli Marouf

Head Mentor

Yomen Sayedsoleman Atassi

MentorMohamad Khaled Al Joumaa

Invigilator

Tamam Hawa / Dima Khalil / Lara Shabea

National Team of Countries

45

Tajikistan
Tajikistan

Muhammad Barotov

Student

Shahzod Nazirov

Muhammadzhon
OtakhonovNuriddin Valizoda

Head Mentor
Khushang Sobirov

MentorDaler Salimov

Invigilator

Ramazon Ziyoev

ThailandThailandSathira JantarakulchaiStudent

Nichawadee
Kanjanakosit

Jirapat Rujirayuk

Lita Tantipraphat

Head Mentor

Torsak Luanphaisarnnont

MentorChaiya Prasittichai

ObserverNattapong Paiboonvorachat / Nisalak Trongsiriwat

Invigilator

Charoensak Mueangkaew / Oratai Rueangsombat / Sakol Warintaraporn

46

The 53rd IChO 2021 Japan

Trinidad
andTobagoTrinidadandTobagoStudent

Vineeta Bujhawan

Jaasiel Edwards

Alayna Ragbar

Aiden Ramgoolam

Head Mentor
Nigel Kevin Jalsa

MentorTerry Mohammed

Invigilator

April Koon-Jagassar / Anton Manoo

TurkeyTurkeySebnem Gul

Student

Goktug Gulsoy

Deniz Guner

Berkan Tarak

Head Mentor
Arif Dastan

MentorYunus Emre Turkmen

Invigilator

Dilgam Ahmedli / Nurullah Saraçoğlu / Baturalp Yalçın

National Team of Countries

47

Turkmenistan
Turkmenistan

Yusup DovletmyradovStudent

Gozel Dovranova

Davut
Muhammetgulyyev

Berdigylych
Rejepbayev

Head Mentor
Nazar Mammedov

MentorSerdar Begenjov

Invigilator

Amangeldi Meretglychov

UkraineUkraineIhor Kholomieiev

Student

Daria Klymenko

Yurii Okis

Head Mentor

Kostiantyn Gavrylenko

MentorDmytro Volochnyuk

Invigilator

Alexander Lyapunov / Makhankova Valeriya48

The 53rd IChO 2021 Japan

Oleksandr Zaporozhets

UnitedArab
Emirates
UnitedArab
Emirates
Student

Ahmed Abdulaziz
Alsabbagh

Vaidik Rajesh Hurkat

Yasmin Mahmood
Abdulla Mohammad Ali

Devavrat VermaHead Mentor

Abdallah El Marhoune

MentorManish Vijay Chhatre

Invigilator

Pooja Badal Debath

UnitedKingdom
UnitedKingdom

Harry John ListStudent

Zachary John McGuire

Rtvik Patel

Alexander Ramsay
Thow

Head Mentor
Ben Pilgrim

MentorAlex Thom

ObserverJl Kiappes / Andrew Taylor

Invigilator

Charlotte Turner

National Team of Countries

49UnitedStatesof America
UnitedStatesof America
Student

Kien Phuong

Nikhil Seshadri

Qiyang Zhou

Yitian Zhu

Head Mentor

Joseph Daniel Houck

MentorEsther Hines

Observer

Lily Lambert Raines / Laura Serbulea

Invigilator

Alvin Collins / David Horwitz / Kelly Love / Malgorzata Thatcher

Uruguay
Uruguay

Agustín Almeida Ahlers

Student

Agustín Corbo Borche

Mariano Díaz Borges

Head Mentor

Santiago Rostán Talasimov

MentorAgustina Vila

Invigilator

Guillermo Bragunde / Laura Posada

50

The 53rd IChO 2021 Japan

Candela S. Gómez

Uzbekistan
Uzbekistan

Sobirjon AmanovStudent

Ikromiddin
Boymahammadov

Durdona
Muxtarxujayeva

Firdavs Sobirov

Head Mentor
Davron Tukhtaev

MentorOrtikboy Eshankulov

Invigilator
Aziz Khasanov

Venezuela
Venezuela

Student

Alberto Josué Alava
CedeñoVerónica Landaeta
Hernández

Head Mentor

Alessandro D. Trigilio

MentorAmalia J. Torrealba

Invigilator

Laury Bravo / María P. Hurtado / Carmelina M. Kurilo / Nayleth Yépez

National Team of Countries

51

VietnamVietnamAnh Duy Nguyen

Student

Anh Le Thao Nguyen

Duong Hoang Nguyen

Phuong Duc Nam Pham

Head Mentor
Ha Ngoc Nguyen

MentorPhong Van Pham

ObserverNgan Thi Bich Nguyen

Invigilator

Hai Thi Hong Le / Thuy Thi Thu Luong / Mo Thi Nguyen / Ha Thi Thu Nguyen

ObserverStudent
Afghanistan

Rahmkhuda Karimi

EcuadorAndrea Fernanda Barcia

KuwaitEssa Menhal Alqallaf

Nepal

Surgeon Bc

Paraguay

Juan Marcos Serafini Careaga

52

The 53rd IChO 2021 Japan

Country

Student

MentorArmenia

4

Australia

4

Observer

Guest

Invigilator

Total

2

1

7

2

4

10

2

10

2

8

4

12

Austria

4

2

Azerbaijan

4

2

2

Bangladesh

42Belarus

4

2

2

8

Belgium

4

2

2

8

Brazil422

9Bulgaria

4

2

4

10

Canada

4

2

4

10

China

4

2

4

2

12

Chinese Taipei

4

2

2

2

10

Costa Rica

3

2

2

7

Croatia

4

2

2

8

Cyprus4

2

2

8

Czech Republic

4

4

1

9

Denmark

4

2

2

8

El Salvador

4

2

4

10

Estonia

4

2

1

7

Finland

4

2

2

9

France4217Georgia

4

2

2

4

12

Germany

4

2

1

3

10

1

7

1

8

1

7

2

1

1

Greece42

Hungary

4

2

Iceland

4

2

India

4

2

1

9

16

Indonesia

4

2

1

4

11

Iran

4

2

2

8

Ireland

4

2

2

4

12

Israel

4

2

1

1

8

Japan

4

2

2

3

12

Kazakhstan

4

2

2

8

Korea

4

2

2

10

Kyrgyzstan

4

2

2

8

Latvia42

1

7

Lithuania

4

2

2

8

Luxembourg

4

2

1

7

Malaysia

4

2

4

10

Mexico4

2

2

8

Moldova

4

2

2

8

Mongolia

4

2

2

10

Montenegro

4

2

2

8

Netherlands

4

2

3

9

1

2

2

1

National Team of Countries

53

Country

Student

Mentor

New Zealand4

Nigeria

Invigilator

Total

2

3

9

3

2

1

6

North Macedonia

4

2

1

7

Norway

4

2

2

8

Oman

4

2

4

10

Pakistan

4

2

3

9

Philippines

4

2

5

11

Poland4

2

1

8Portugal

4

2

2

8

Qatar

4

2

2

10

Romania

4

2

3

9

Russian Federation

4

2

2

1

9

Saudi Arabia

4

2

2

1

9

Serbia4228Singapore

4

2

2

9

Slovakia

4

2

1

7

Slovenia

4

2

2

8

South Africa

4

2

2

8

Sri Lanka

4

2

4

10

Sweden

4

2

1

3

10

Switzerland

4

2

3

2

11

Syria

4

2

3

9

Tajikistan

4

2

1

7

Guest

1
2

1

Thailand

4

2

3

11

Trinidad and Tobago

4

2

2

8

Turkey42

39Turkmenistan

4

2

1

7

Ukraine

4

2

2

8

United Arab Emirates

4

2

1

7

United Kingdom

4

2

2

1

9

United States of America

4

2

2

4

12

Uruguay

4

2

2

8

Uzbekistan

4

2

1

7

Venezuela

2

2

4

8

Vietnam

4

2

4

11

2

1

Afghanistan

1

1

Ecuador1

1

Kuwait

1

1

Nepal

1

1

Paraguay

1

1

total

54

ObserverThe 53rd IChO 2021 Japan

312

160

51

1

185

709

Results

Gold Medal
Rank

Name

Country

Medal

Total

1

Shu Yang

China

Gold

97.57

2

Zhangyi Huang

China

Gold

97.08

3

Xinyu Cai

China

Gold

95.61

4

Bangsen Zhao

China

Gold

94.39

5

Sobirjon AmanovUzbekistan

Gold

92.14

6

Mircea Raul Bodrogean

Romania

Gold

90.54

7

Aleksandr E. Trofimov

Russian Federation

Gold

88.67

8

Anh Duy Nguyen

Vietnam

Gold

88.43

9

Bo-An Chen

Chinese Taipei

Gold

88.33

10

Georgii M. Zhomin

Russian Federation

Gold

88.13

11

Chun-Cheng Ting

Chinese Taipei

Gold

87.96

12

Phuong Duc Nam Pham

Vietnam

Gold

86.86

13

Qiyang Zhou

United States of America

Gold

86.83

14

Berkan Tarak

Turkey

Gold

86.20

15

Chen Yizhou

Singapore

Gold

85.35

16

Alexander Ramsay Thow

United Kingdom

Gold

84.33

17

Rui-Xi Wang

Chinese Taipei

Gold

84.05

18

Cheng Jun, Nicholas Goh

Singapore

Gold

83.99

19

Nir Cohen

Israel

Gold

83.71

20

Timofey A. Charkin

Russian Federation

Gold

83.59

21

Tudor Lile

Romania

Gold

82.69

22

Adarsh Reddy Madur

India

Gold

81.99

23

Mahbod Alian Fini

Iran

Gold

81.76

24

Deniz Guner

Turkey

Gold

81.34

25

Andrei S. Tyrin

Russian Federation

Gold

81.31

26

Dhananjay Raman

India

Gold

81.30

Results

57

Rank

Name

Country

Medal

Total

27

Yitian Zhu

United States of America

Gold

81.03

28

Filip Hůlek

Czech Republic

Gold

80.95

29

Harry John List

United Kingdom

Gold

80.90

30

Anh Le Thao Nguyen

Vietnam

Gold

80.33

31

Mahyar Afshinmehr

Iran

Gold

80.17

32

Myeongjin Shin

Korea

Gold

80.14

33

Alexandru Catalin Dianu

Romania

Gold

79.82

Silver Medal

58

Rank

Name

Country

Medal

Total

34

Duong Hoang Nguyen

Vietnam

Silver79.05

35

Stefan Dimitriu

Romania

Silver

78.81

36

Sebnem Gul

TurkeySilver

78.81

37

Uladzislau Hlatankou

BelarusSilver78.74

38

Alphonsus Yu Xiang Neo

Singapore

Silver77.76

39

Michal Piotr Lipiec

PolandSilver77.48

40

Oscar Dong

Australia

Silver

77.22

41

Seung Jae Kang

Korea

Silver

76.88

42

Nikhil Seshadri

United States of America

Silver

76.11

43

Faatih Regind Qashash Roman

Indonesia

Silver76.06

44

Bernard Tze Wei Kwee

Singapore

Silver75.83

45

Hsuan-Ting Lin

Chinese Taipei

Silver74.87

46

Mahit Rajesh Gadhiwala

India

Silver

74.29

47

Seyed Mohammad Hossein Barakati

IranSilver

72.82

48

Oisín Colm Ó Feinneadha

IrelandSilver72.75

49

Oleksandr Zaporozhets

UkraineSilver71.96

50

Goktug Gulsoy

TurkeySilver

70.76

The 53rd IChO 2021 Japan

Rank

Name

Country

Medal

Total

51

Shahzod Nazirov

Tajikistan

Silver

70.49

52

Hee Seong Yoon

Korea

Silver

69.93

53

Jirapat Rujirayuk

ThailandSilver69.79

54

Jovan Marković

SerbiaSilver

69.42

55

Linus Albert Schwarz

Germany

Silver

69.32

56

Muhammad Barotov

Tajikistan

Silver68.80

57

Vinicius da Silveira Lanza Avelar

BrazilSilver

68.34

58

Lucio Saracco

Hungary

Silver

67.68

59

Ioannis Karageorgiou

GreeceSilver

67.17

60

Nichawadee Kanjanakosit

ThailandSilver

67.03

61

Davut Muhammetgulyyev

Turkmenistan

Silver

66.40

62

Takahiro Takemoto

Japan

Silver

65.92

63

Kohei Nishiura

Japan

Silver65.65

64

Bruno Andrzej Skoczen

PolandSilver65.63

65

Khaidar Kairbek

Kazakhstan

Silver

65.20

66

Mohammad Solaiman AlHadlaq

Saudi Arabia

Silver

64.93

67

Marek Pavlica

Czech Republic

Silver64.38

68

Ehsan Naderi Donig

Iran

Silver

64.21

69

Patrik Žnidaršič

Slovenia

Silver

64.00

70

Seoyeon Kim

Korea

Silver

63.13

71

Gerel Bayarmagnai

Mongolia

Silver

62.88

72

Temujin Orkhon

Mongolia

Silver62.78

73

Kien Phuong

United States of America

Silver

62.56

74

Tong Wu

IrelandSilver

61.87

75

Zachary John McGuire

United Kingdom

Silver

61.69

76

Rishit Singla

India

Silver61.60

77

Andy Cai

CanadaSilver

61.36

78

Lita Tantipraphat

ThailandSilver60.66

79Džonatans Miks Melgalvis

LatviaSilver60.60

80

Yuya Koike

Japan

Silver

60.54

81

Mohammad Rashed AlHudaithi

Saudi Arabia

Silver60.11

Results

59

Rank

Name

Country

Medal

Total

82

Abdulaziz Abdulrahman AlJuaid

Saudi Arabia

Silver59.89

83

Matúš Tomčo

Slovakia

Silver

59.85

84

Itamar Steinitz

IsraelSilver59.60

85

Gozel Dovranova

Turkmenistan

Silver

59.56

86

Ron Angelo A. Gelacio

Philippines

Silver

58.34

87

Simon Bukovšek

Slovenia

Silver57.50

88

Michael Schembera

Austria

Silver

57.20

89

Sanzhar Bissenali

Kazakhstan

Silver

57.17

90

Tim Bastian Enders

Germany

Silver57.12

91

Pavel Atanasov Nikolov

Bulgaria

Silver56.83

92

Berdigylych Rejepbayev

Turkmenistan

Silver56.72

93

Dávid Benkő

Hungary

Silver56.28

94

Yusup Dovletmyradov

Turkmenistan

Silver56.10

95

Madiyar Kassymaly

Kazakhstan

Silver55.62

96

Povilas Dapsys

Lithuania

Silver55.52

97

Nathan Wayne F. Ariston

Philippines

Silver55.36

98Daniils Kargins

LatviaSilver55.21

99

Jakub Krzysztof Kwiatkowski

PolandSilver

54.81

100

Ihor Kholomieiev

UkraineSilver

54.71

Bronze Medal

60

Rank

Name

Country

Medal

Total

101

Kevin Lius Bong

Indonesia

Bronze53.77

102

Tadas Danilevicius

Lithuania

Bronze53.71

103

Khanim Yagublu

Azerbaijan

Bronze53.59

104

Sathira Jantarakulchai

ThailandBronze53.30

105

Irmuun Altankhuyag

Mongolia

Bronze53.07

The 53rd IChO 2021 Japan

Rank

Name

Country

Medal

Total

106

Kamil Mambetov

Kyrgyzstan

Bronze52.79

107

Neta Eiger

IsraelBronze52.75

108

István Babcsányi

Hungary

Bronze52.51

109Samuil Vladimirov Petkov

Bulgaria

Bronze52.42

110

Durdona Muxtarxujayeva

Uzbekistan

Bronze52.18

111

Lazar Savić

SerbiaBronze52.12

112

Hanif Muhammad ZhafranIndonesia

Bronze51.97

113

Darko Stojchev

North Macedonia

Bronze51.86

114

Vladislavs Tiščenko

LatviaBronze51.06

115

Maciej Swiatek

Austria

Bronze50.96

116

Keith Wong

Australia

Bronze50.89

117

Johann Sora Blakytny

Germany

Bronze50.81

118

Andrei Banica

CanadaBronze50.65

119

Firdavs Sobirov

Uzbekistan

Bronze50.47

120

Ketevan Peranidze

Georgia

Bronze50.47

121

Abdur-Raheem Idowu

NorwayBronze50.24

122

Ruben Tapia

FranceBronze49.63

123

Austin Lin

Australia

Bronze49.56

124

Patrik Fábrik

Slovakia

Bronze49.56

125

Aigerim Turuspekova

Kazakhstan

Bronze49.45

126

Nathanael Reza Putra Widjaja

Indonesia

Bronze49.42

127

Edvards Jānis Treijs

LatviaBronze49.41

128Georgi Neliyanov Nedyalkov

Bulgaria

Bronze49.28

129

Salman Huseynov

Azerbaijan

Bronze48.49

130

Cassia Caroline Aguiar da Ponte

BrazilBronze48.22

131Angelina Rogatch

BelarusBronze48.04

132

Benedek Sajósi

Hungary

Bronze47.96

133

Alina Tumashyk

BelarusBronze47.73

134

Nariman Shirinli

Azerbaijan

Bronze47.44

135

Saeed Sultan Baghdadi

Saudi Arabia

Bronze47.39

136

Ahmad Thaer Ater

Syria

Bronze47.36

Results

61

62

Rank

Name

Country

Medal

Total

137

Maha Ali

Syria

Bronze47.32

138

Jorge García-Ponce

MexicoBronze46.82

139

Michael Li

CanadaBronze46.71

140

Lukas Rost

Austria

Bronze46.48

141

Teodor Svilenov Maslyankov

Bulgaria

Bronze46.40

142

Nadun Naveendra Rajapaksha

Sri Lanka

Bronze46.15

143

Yurii Okis

UkraineBronze46.09

144

Dimitrije Gligorovski

SerbiaBronze45.98

145

Achira Hansindu Kelambi Arachchige

Sri Lanka

Bronze45.71

146

Marina Malta Nogueira

BrazilBronze45.55

147Fran Miletic

Croatia

Bronze45.31

148

Haruhi IsseJapan

Bronze45.22

149

Jernej Birk

Slovenia

Bronze45.05

150

Yangyi Qi

SwedenBronze45.03

151

Aleksandr Beditski

Estonia

Bronze44.70

152

Vincent Ng

Australia

Bronze44.41

153

Anas Abbas

Syria

Bronze44.28

154Adam Szymon Sukiennik

PolandBronze44.24

155

Tomáš Heger

Czech Republic

Bronze44.08

156

Ikromiddin Boymahammadov

Uzbekistan

Bronze43.17

157

Fynn Lasse Noah Kessels

Germany

Bronze43.07

158

Jakub Sochor

Czech Republic

Bronze43.03

159

Emilio Alonso Venegas-Hernandez

MexicoBronze42.97

160

Michael Estes

Denmark

Bronze42.57

161

Liis Siigur

Estonia

Bronze42.57

162

Jochem van den Broek

Netherlands

Bronze42.53

163

Nino Abesadze

Georgia

Bronze42.01

164

Hayk Aghekyan

Armenia

Bronze41.82

165

Aames Juriel B. Morales

Philippines

Bronze41.19

166

Théodore Halley

FranceBronze40.99

167

Valerian Mocreac

Moldova

Bronze40.56

The 53rd IChO 2021 Japan

Rank

Name

Country

Medal

Total

168

Alexandre Bloquel

FranceBronze40.41

169

Laimis Jurkenas

Lithuania

Bronze40.39

170

Mahsati Piriyeva

Azerbaijan

Bronze40.28

171

Daan Roger Stan Vanhaecke

Belgium

Bronze40.26

172

Simonas Melaika

Lithuania

Bronze40.10

173

Sandro Pfammatter

Switzerland

Bronze39.92

174

Ioane Kapanadze

Georgia

Bronze39.86

175

Fredi Manuel Barraza Hernandez

El Salvador

Bronze39.45

176

Tatiana Sviriniuc

Moldova

Bronze39.35

177

Mason Minghan Liu

New ZealandBronze39.27

178

Ján Plachý

Slovakia

Bronze39.06

179

Oscar Eric Moran Despard

IrelandBronze38.93

180

Leonid Asatryan

Armenia

Bronze38.91

181

Terry Wang

CanadaBronze38.77

182

Hana Gabriela Albuquerque Sousa

BrazilBronze38.75

183

Tal Sason

IsraelBronze38.69

184

Tigran Harutyunyan

Armenia

Bronze38.53

185

Andrei Kornijenko

Estonia

Bronze38.41

186

Nevena Stojković

SerbiaBronze38.31

187

Adelina Andrei

Moldova

Bronze38.16

188

Samuel Kolesár

Slovakia

Bronze37.99

189

Sebastian Jacob Krikke

Netherlands

Bronze37.50

190Paul Johann Dorfer

Austria

Bronze37.47

191

Lin Bigom-Eriksen

Denmark

Bronze37.19

192

Manujaya Praveen Wijesinghe

Sri Lanka

Bronze36.84

193

Kiryl Maroz

BelarusBronze36.57

194

Maxim Cojocari-Goncear

Moldova

Bronze36.06

Results63

Honorable
mention

64

Rank

Name

Country

Medal

Total

195

Bumchin Dolgormaa

Mongolia

Honorable
Mention

35.43

196

Abhinav Chawla

New Zealand

Honorable
Mention

35.00

197

Aku Hertell

Finland

Honorable
Mention

34.86

198

Daria Klymenko

UkraineHonorable
Mention

34.83

199

João Pedro Bonito CaldeiraPortugal

Honorable
Mention

34.66

200

Théo Mignen

FranceHonorable
Mention

34.60

201

Ali Marouf

Syria

Honorable
Mention

34.56

202

Olga Jerkovic Peric

Croatia

Honorable
Mention

34.45

203

Sam Wuji Zhuang

New Zealand

Honorable
Mention

34.40

204

Samuel Klaver

Finland

Honorable
Mention

34.27

205

Vid Kavčič

Slovenia

Honorable
Mention

33.37

206

Jessica Rebekka Kurmann

Switzerland

Honorable
Mention

33.21

207

Safwan Sakib

Bangladesh

Honorable
Mention

32.87

208

Gerardo Emiliano Gutierrez-Alvarez

MexicoHonorable
Mention

31.69

209

Rafael Dux

Luxembourg

Honorable
Mention

31.43

210

Aoife Mary Morris

Ireland

Honorable
Mention

31.06

211

Henri Kärpijoki

Finland

Honorable
Mention

30.82

212

Dinithi Shalika Madhubhashini

Sri Lanka

Honorable
Mention

30.61

213

Daniel Jiyoun Jang

New Zealand

Honorable
Mention

30.57

214

Athanasios Feidakis

GreeceHonorable
Mention

30.17

215

Jean-Marc Furlano

Luxembourg

Honorable
Mention

29.88

216

Vaidik Rajesh Hurkat

United Arab Emirates

Honorable
Mention

28.98

217

Mahin Kamal Sawdager

Bangladesh

Honorable
Mention

28.76

218

Khalid Hasan Tuhin

Bangladesh

Honorable
Mention

28.62

The 53rd IChO 2021 Japan

Others
Rank

Name

Country

Total

219

Emmanuel Sotomea-Renova

Mexico28.20

220

Simen Mannsåker

Norway28.15

221

Lizi Darchia

Georgia

27.62

222

Joachim Julian Klaussen

Norway25.84

223

Dimitrios Stylianakis

Greece25.71

224

Anastasia Aleksandrovna Sandamirskaya

Switzerland

25.41

225

Theodor Malte Novrup Redvall

Denmark

25.37

226

Nadezhda Ondrina

Kyrgyzstan

25.37

227

Nihit Agarwal

Qatar

25.34

228

Anja Spasovska

North Macedonia

25.09

229

Marko Preocanin

Croatia

24.75

230

Joseph Eghenevwegba Ikuru

Nigeria

24.57

231

Mariana Vilela Marta Rio Costa

Portugal

24.45

232

Sevada Nersisyan

Armenia

24.03

233

Jan Stojanovski

North Macedonia

23.86

234

Danijel AleksicMontenegro

23.62

235

Devavrat Verma

United Arab Emirates

22.86

236

Azamat Salamatov

Kyrgyzstan

22.58

237

Emily Alejandra Crespin Guerra

El Salvador

22.31

238

Melanie Muntz

Denmark

22.25

239

Ivan Reshetnikov

Kyrgyzstan

21.95

240

Vasileios Papastamopoulos

Greece21.39

241

Tina Kalleson

Norway21.12

242

Beatriz Crisóstomo Valério Figueiredo

Portugal

20.68

243

Leopold Kall

Sweden20.48

244

Tawhid Muhammad Mubashwir

Bangladesh

20.47

245

Mihail Trajkov

North Macedonia

20.42

246

Kristoff John F. PadillaPhilippines

20.34

Results

65

66

Rank

Name

Country

Total

247

Jef H. K. Van Eester

Belgium

19.77

248

Lim Xu Yao

Malaysia

19.77

249

Yasmin Mahmood Abdulla Mohammad Ali

United Arab Emirates

19.52

250

Jasmin Jasarevic

Croatia

19.20

251

Agustín Corbo Borche

Uruguay

19.02

252

Ayesha Junaid

Pakistan

18.60

253

Erik Bryland

Sweden18.22

254

Mitchell Rikken

Netherlands

17.95

255

Nuriddin Valizoda

Tajikistan

16.99

256

Giorgos Papachristodoulou

Cyprus

15.63

257

Tiago Miguel Gomes de Sousa

Portugal

15.53

258

Dagur Bjorn Benediktsson

Iceland

14.71

259

Otto Keronen

Finland

14.59

260

Raphaël Menasce

Luxembourg

14.43

261

Mariano Díaz Borges

Uruguay

14.36

262

Luis Ronaldo Chavez Escamilla

El Salvador

13.81

263

Muhammad Mahdi da Costa

South Africa

13.57

264

Verónica Landaeta Hernández

Venezuela

13.42

265

Agustín Almeida Ahlers

Uruguay

13.25

266

Alberto Josué Alava Cedeño

Venezuela

12.91

267

Antoine Robin Chèvre

Switzerland

12.84

268

Louis PecheurBelgium

12.83

269

Lukas Schieble

Belgium

12.69

270

Christiana Kosta

Cyprus

12.62

271

Max Rudolf Antonius Karel van Hest

Netherlands

12.62

272

Arwa Al Hashimi

Oman

12.53

273

Wong Yi Yang

Malaysia

12.49

274

Elsa Bitzén

Sweden12.38

275

Telma Jeanne Bonthonneau

Iceland

12.34

276

Jessica Thackeray

Cyprus12.09

277

Bernie Lim Wei Yuan

Malaysia

12.03

278

Muhammad Yahya

Pakistan

11.58

279

Laurent Bommertz

Luxembourg

11.48

The 53rd IChO 2021 Japan

Rank

Name

Country

Total

280

Sushanthi Anandaraja

Qatar

10.75

281

Sara Fahed Al ali Alahmad

Qatar

9.07

282

Muhammad Ismail

Pakistan

8.71

283

Iva Djurickovic

Montenegro

8.42

284

Ahmed Abdulaziz Alsabbagh

United Arab Emirates

8.36

285

Stylianos Tamasios

Cyprus

8.05

286

Daniel Heidar Jack

Iceland

7.88

287

Rameesha Khursheed

Pakistan

7.77

288

Shawn Vernon Wong Siang Ray

Malaysia

7.72

289

Fanny Mariana Solís González

Costa Rica

7.33

290

Olivia Sojourner Dixon

Costa Rica

7.29

291

Maryam Al-Hatmi

Oman

7.25

292

Candela S. Gómez

Uruguay

7.08

293

Muhammadzhon Otakhonov

Tajikistan

7.06

294

Abdullah Al-Azri

Oman

6.99

295

Alayna Ragbar

Trinidad and Tobago

6.89

296

Aiden Ramgoolam

Trinidad and Tobago

6.21

297

Vineeta Bujhawan

Trinidad and Tobago

6.12

298

Lujaina Al Badi

Oman

5.61

299

Isak Hugi Einarsson

Iceland5.58

300

Ignacio Herrera Gamboa

Costa Rica

5.19

301

Mohammed TanweerAlli

South Africa

5.02

302

Jaasiel Edwards

Trinidad and Tobago

4.55

303

Asmahan Abdulaziz Al-Kuwari

Qatar

4.54

304

Erkam Cihan Caglak

South Africa

4.33

305

Brenda Nicole Juarez Marroquín

El Salvador

4.01

306

Ifeanyichukwu Valentine Umeanyika

Nigeria

2.99

307

Ksenija Tadic

Montenegro

2.79

308

Abdul-Baasit Salie

South Africa

1.92

309

Milica Zizic

Montenegro

1.41

unfortunate
absence

Siim Tiivel

Estonia-

unfortunate
absence

Rtvik Patel

United Kingdom-

unfortunate
absence

Winston Ukpong

Nigeria-

Results67

Total Score
Maximum

97.566

Minimum

1.415

Average43.913Standard
Deviation

24.259Problem No.

Q1 (11)Q2 (11)Q3 (8)

Q4 (11)

Q5 (12)

Q6 (13)Q7 (13)

Q8 (11)

Q9 (10)Maximum

11

11

8

11

12

13

13

11

10

Minimum

0

0

0

0

0

0

0

0

0

Average

5.395

3.942

3.422

5.448

5.140

4.743

5.917

4.906

5.001

Standard
Deviation

3.289

3.239

2.725

3.781

3.400

3.573

4.308

3.454

3.464

100

90

Distribution of Scores

Gold
Medal
SilverMedal

80

BronzeMedal

70

Honorable
mentionScores

60

50

40

30

20

0

1
5
9
13
17
21
25
29
33
37
41
45
49
53
57
61
65
69
73
77
81
85
89
93
97
101
105
109
113
117
121
125
129
133
137
141
145
149
153
157
161
165
169
173
177
181
185
189
193
197
201
205
209
213
217
221
225
229
233
237
241
245
249
253
257
261
265
269
273
277
281
285
289
293
297
301
305
309

10

Students
68

The 53rd IChO 2021 Japan

Histogram of Points
Total Score (every 5 points)
35

25
20
15
10

Score (every 5 points)
Q1 (11 points)
Hydrogen at a Metal Surface

70

40

60

35

50

30
25

40

20

30

15

20

10

10

5
0
[0 , 1 ](1 , 2 ](2 , 3 ](3 , 4 ](4 , 5 ](5 , 6 ](6 , 7 ](7 , 8 ](8 , 9 ](9 , 10 ](10 , 11 ]0
[0 , 1 ](1 , 2 ](2 , 3 ](3 , 4 ](4 , 5 ](5 , 6 ](6 , 7 ](7 , 8 ](8 , 9 ]PointsPointsQ3 (8 points)
Lambert-Beer Law?

Q4 (11 points)
The Redox Chemistry of Zinc

60

90

Number of students

Number of students

100(9 , 10 ](10 , 11 ]

50

80
70

40

60

30

50
40

20

30

10

20
10
0

Q2 (11 points)
Isotope Time Capsule80

45

Number of students

Number of students

50(96 , 101 ](91 , 96 ]

(86 , 91 ]

(81 , 86 ]

(76 , 81 ]

(71 , 76 ]

(66 , 71 ]

(61 , 66 ]

(56 , 61 ]

(51 , 56 ]

(46 , 51 ]

(41 , 46 ]

(36 , 41 ]

(31 , 36 ]

(26 , 31 ]

(21 , 26 ]

(16 , 21 ]

(11 , 16 ]0

(6 , 11 ]5[1 , 6 ]Number of students

30[0 , 1 ](1 , 2 ](2 , 3 ](3 , 4 ](4 , 5 ]Points(5 , 6 ](6 , 7 ](7 , 8 ]0[0 , 1 ](1 , 2 ](2 , 3 ](3 , 4 ](4 , 5 ](5 , 6 ](6 , 7 ](7 , 8 ](8 , 9 ](9 , 10 ](10 , 11 ]PointsResults69

Q5 (12 points)
Mysterious Silicon

80

Number of students

Number of students

45
40

70

35

60

30

50

25

40

20

30

15

20

10

10

5
0
[0 , 1 ]50(1 , 2 ](2 , 3 ](3 , 4 ](4 , 5 ](5 , 6 ](6 , 7 ](7 , 8 ]Points(9 , 10 ](11 , 12 ]
(8 , 9 ](10 , 11 ]Q7 (13 points)
Playing with Non-benzenoid
Aromaticity

0(1 , 2 ](3 , 4 ](5 , 6 ](7 , 8 ](9 , 10 ](11 , 12 ][0 , 1 ](2 , 3 ](4 , 5 ](6 , 7 ](8 , 9 ](10 , 11 ]
(12 , 13 ]PointsQ8 (11 points)
Dynamic Organic Molecules
and Their Chirality

80

Number of students

Number of students60

Q6 (13 points)
The Solid-State Chemistryof Transition Metals

70

60

40

50

40

30

30

20

20

10
0

10

(1 , 2 ](3 , 4 ](5 , 6 ](7 , 8 ](9 , 10 ](11 , 12 ][0 , 1 ](2 , 3 ](4 , 5 ](6 , 7 ](8 , 9 ](10 , 11 ]
(12 , 13 ]0[0 , 1 ](1 , 2 ](2 , 3 ]Points(4 , 5 ]

80
70
60
50
40

30
20
10
0

[ 0 , 1 ] (1 , 2 ] (2 , 3 ] (3 , 4 ] (4 , 5 ] (5 , 6 ] (6 , 7 ] (7 , 8 ] ( 8 , 9 ] (9 , 10 ]Points70

The 53rd IChO 2021 Japan(5 , 6 ]PointsQ9 (10 points)
Likes and Dislikes of Capsule

90

Number of students(3 , 4 ](6 , 7 ](7 , 8 ](8 , 9 ](9 , 10 ](10 , 11 ]

Certificate and Medals

No.

8

Aug. 1

2021
Osaka TaroJapan

Certificate
Cover illustration : Award Ceremony

Medal Design Concept: “The Chemical Vortex Leading to the Future”

Designer: Sakiko MatsumotoF

rom the center to the edge, the entire medal forms the shape of a vortex, giving theimpression of a whirling motion. This movement represents the global impact andupcoming success of young students, originating at IChO2021 Japan. Through the designs
found on both sides of the medal, IChO2021 supports the bright future of the contestants.

The obverse side features three kinds of popular auspicious patterns to express aspects ofJapanese culture.

The reverse side contains the logo, which is represented in a simple and emphatic way

through an image that spreads across the world.

Seigaiha (青海波) translates to blue ocean waves. The endlessly

calm waves are a prayer for long-lasting happiness and a peacefullife.

Shippō Tsunagi (七宝つなぎ) is a pattern of connecting circles, expressing

a wish for happiness, harmony, and connection. This connection is asvaluable as the Seven Treasures of Buddhism: gold, silver, lapis lazuli,
agate, seashell, amber, and coral.

Asanoha (麻の葉) is a pattern representing hemp leaves. Because

hemp is resilient, grows vigorously, and requires little care, it is often

used as a pattern in the kimono of young children in the hope that theygrow up big and strong. It is also meant to ward off evil.

The ribbon represents the image of a whirlpool flowing from the medal
in indigo, black, and vermillion, which is the color of Japan. The design
also expresses the impact that the students will have in the world.

72

The 53rd IChO 2021 Japan

Obverse side

Reverse side

Certificate and Medals

73

Memento and Gifts

Memento and Gifts
Our memento and gifts, presented to all students, mentors and observers, consist of a tin
water pot (pewter ware), an “azuma bukuro” and a tote bag with our catch-phrase andcharacters printed. Some explanations are given below.

【Tin water pot】
A tin water pot has been selected as memento because tin ware is known as one of traditional
crafts famous for Osaka, where the 53rd IChO 2021 Japan was originally planned to beheld.
Tin has been used since very early in the human history, due to its easy-to-scouring
nature and its relatively low melting point (231.9 ℃). Tin water pot made around 1500
B.C. has been discovered in Egypt. Pewter ware, made of 97% tin, was brought to Japanfor the first time about 1300 years ago; it seems to have travelled along the Silk Road andarrived via China. Since then in Japan tin had only been used as table ware for ruling classand as tools for Buddist temples and shrines, until a huge tin mine was discovered in the
17th century, after when pewter ware began to be used commonly as utensils for serving
and drinking sake and tea.
It is known that a tin processing factory existed in Osaka at the latest in 1679. The
production of tin and pewter ware established itself as a major industry in Osaka thanks to
its position as a distribution hub. The tin ware made in Osaka was designated Traditional
Craft as “Osaka Naniwa Pewterware” in 1983.

【Azuma bukuro】“Azuma bukuro”, meaning “east bag”, is a traditional Japanese ecofriendly carry andshopping bag made of light and soft cloth. This type of bag was originally made in Edo(old name of Tokyo) during the Edo era (1603~1868), where is located from east (azuma)
from Kyoto, old capital of Japan. Kyoto people used it conveniently by calling “Azuma
bukuro”. The “Azuma bukuro” should be useful in our modern life.

【Tote bag】
The tote bag has our catch phrase “Chemistry! It’s Cool!”, as well as five cards of element
symbols O, Mo, Te, Na, Si, carried by our characters: “OMOTENASI” in total means warm
hospitality in Japanese. We hope that this will be used for a long time as a commemorative
item of the 53rd IChO 2021 Japan.
76

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Memento and Gifts

Memento and Gifts

77

Ceremony78

The 53rd IChO 2021 Japan

IChO 2021 Japan Photo CollectionIChO 2021 Japan Photo Collection

Examination79

Meeting

80

The 53rd IChO 2021 Japan

IChO 2021 Japan Photo CollectionIChO 2021 Japan Photo Collection

Activity

Explainers videos for the practical tasks @Kindai Univ.

Virtual Visit to SPring-8

81Secretariat

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The 53rd IChO 2021 Japan

IChO 2021 Japan Photo Collection

Examination

Examination Guideline

53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline

IChO 2021 Japan
IChO Japan 2021
Examination Guideline
Examination
Guideline

10 June, 2021
Version 2.2
Organizing Committee of IChO2021 Japan

1. General
1-1. Purpose of thisThisGuideline
Guideline
Due to the COVID-19 pandemic, IChO2021 Japan will be held remotely. This guideline
is published to ensure that the theoretical examination for this remote IChO is
conducted appropriately.
This document institutes the rules to be followed. It also provides countries withrecommended operational methods to protect their delegations from potential (or false)
accusations of cheating. Please read this document carefully.
1-2. Time Zone
All dates and times on this document are based on Japan Standard Time (JST), which
is Coordinated Universal Time (UTC) +9 hours. Japan does not use daylight saving
time during the summer.
1-3. Future Updates of This Document
This document may be updated in the future. When a modification is made to thisdocument, the IChO2021 Organizing Committee will announce the modification
immediately, and send the updated version of the guideline to all country coordinators.
2. Examination Date and Timetable2-1. Examination Date
The theoretical examination will take place on 28 July, 2021.
2-2. Examination Time- The duration of the examination is 5 hours.
- The details of the examination (printing time, starting time, ending time, scanningtime, times and length of bathroom breaks, and calculator model) must be reported byinvigilators. The report form to be completed by invigilators will be provided with thestudent examination papers.

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53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
2-3. Examination Timetable- The official examination period is 7:00 pm to 12:00 pm JST. If that period is notconvenient in the time zone of the participating country, the examination may start up to
5 hours earlier or later. However, in this case, the participating students must observe a
total communication ban (blackout) that includes the official examination period. For
example, if they start earlier, they must remain secluded until 12:00 pm JST, and if they
start later, they must be in isolation from 7:00 pm JST. If the participating country
wishes to further change their examination time (for example, further earlier start), they
may consult with the Organizer.
- All competitors in each country must have the same examination timetable to avoid illintentioned communication among competitors. Countries with multiple time zones
must set their timetable on the basis of one specific time zone and conduct theexamination accordingly.
- All countries must submit their choices for starting time, location and recording
method via the registration site by 30 June.
2-4. Management of the Examination- The preparation of the examination (discussions, voting, translation, printing) will be
conducted using Oly-Exam software. Mentors will read, comment and vote on, andtranslate the examination text using the Oly-Exam software. Only a browser andinternet access are necessary.
- Manuals for the Oly-Exam software can be found at https://demo.oly-exams.org/docs/
In the event of any difficulties, mentors and invigilators should refer to the manual. The
Organizing Committee will also provide technical support during IChO2021.
- The mentor and the invigilator for each country will receive individual accounts toaccess Oly-Exam.
- Online training for Oly-Exam will be held at 9:00 pm JST on 23 July via Zoom. The
details of the Zoom meeting will be announced separately. All mentors and invigilators
are expected to attend the training. Observer countries are also invited. The training
session will be recorded, and the link to the recorded file will be available during
IChO2021.
3. Examination Conditions
3-1. Location of Examination- The examination location must be a calm and quiet room with electricity, PC or
smartphone, web camera, microphone, high quality printer, scanner with PDFconversion software, and stable internet connection. Each location will be checked via
Zoom before the examination.
- It is the responsibility of the country to maintain the location in a state suitable for the88

The 53rd IChO 2021 Japan53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
examination. No additional time will be given, even if the examination is interrupted asa result of local problems.
- The examination location should not be the home of a student or a student's relative.
- A single location for the full number of 4 students is highly preferred. If legal travel
restrictions in the country forbid a single location, multiple locations for one country are
acceptable. In this case, all locations must follow the same examination timetable, andmust meet all the requirements. All locations must be notified to the IChO2021
Organizer with the names of the invigilators.
- The students in each location are to be supervised by 1 or 2 invigilators during theexamination.
- The students must maintain an appropriate distance from each other in theexamination room.
3-2. Invigilators- Invigilators must be independent of the mentors, must have no relationship withstudents and must have no other activity in IChO2021. Invigilators should be sociallywell-established persons such as school principals. The names, positions, andaffiliations of the invigilators will be open, as well as those of the mentors.
- Invigilators should not be a parent or a relative of a student.
- Each delegation must register all invigilators at the registration site.
- The invigilators need a good command of English.
- Invigilators will receive an individual account to access Oly-Exam. This account only
allows them to access the PDF files of the official English version and final translated
version of the problems, and to upload the scanned answers.
- Invigilators must complete the downloading and the printing of the English version
and the final translated version of the problems for each student before starting theexamination. The problems and answer sheets must be printed clearly. The Organizing
Committee will not take any responsibility if an unclear print-out results in incorrect
answers given by a student.
- Invigilators should clearly announce the examination timetable to the students before
the examination.
- Students are not allowed to use any electronic communication devices (e.g.,smartphone, computers, smartwatches) during the examination and between 7:00 pm
and 12:00 pm JST. Taking account of different examination starting and ending times,
the total blackout periods are as follows:
Exam start
Exam end
Total blackout period
2:00 pm JST
7:00 pm JST
2:00 pm - 12:00 pm JST
3:00 pm JST
8:00 pm JST
3:00 pm - 12:00 pm JST
4:00 pm JST
9:00 pm JST
4:00 pm - 12:00 pm JST

Examination89

53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
5:00 pm JST
6:00 pm JST
7:00 pm JST

10:00 pm JST
11:00 pm JST
12:00 pm JST

5:00 pm - 12:00 pm JST
6:00 pm - 12:00 pm JST
7:00 pm - 12:00 pm JST

8:00 pm JST
9:00 pm JST
10:00 pm JST
11:00 pm JST
12:00 pm JST*: 29 July

1:00 am* JST
2:00 am* JST
3:00 am* JST
4:00 am* JST
5:00 am* JST

7:00 pm 7:00 pm 7:00 pm 7:00 pm 7:00 pm -1:00 am* JST
2:00 am* JST
3:00 am* JST
4:00 am* JST
5:00 am* JSTStudents are to give their devices to the invigilators before the blackout period shown
above. The invigilators will store them for the total blackout period. If the total blackout
period includes mid-night or early morning, the invigilators may store them until thenext day or from a day before the examination day. The invigilators must ensure thatthe students do not use any computers installed in the examination location over the
relevant total blackout period.
- Invigilators must not allow the students to open the booklet of problems before theexamination starts.
- After the examination, invigilators should scan all answer sheets to prepare one PDF
file per student, sorting the sheets in the order of the page numbers. All PDF files
should be submitted to the IChO2021 Organizer using Oly-Exam within 2 hour after theend of the examination. The answer sheets must be scanned clearly and properly. The
Organizing Committee will not take any responsibility if grading is impossible due tounreadable scanning. Only a PDF format file is acceptable.
- Students are not supposed to ask questions during the exam. Invigilators are not tospeak with students other than to issue the instructions to begin and end theexamination. Students may view the official English version of the examination only
when they request clarification of a problem.
- Invigilators may prepare water and snacks or refreshments for the students outside
the examination room.
- It is strongly recommended that recording, printing, scanning and uploading files aretested before the examination.
3-3. Equipment- Only a non-programmable calculator, good writing pen and a ruler can be used during
the examination.
- The calculator should be a scientific electronic calculator by which logarithmic
function, using both base 10 and e, exponential function, and root can be calculated.
Students must be familiar with how to use the calculator, and can use their own
calculator. The brand and the model name or number of the calculator must be notified

90

The 53rd IChO 2021 Japan53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guidelinefrom the registration site.
- Students should write their answers only using a pen with dark ink. The invigilators
may test the printing and scanning process in advance for readability.
3-4. Recording
Videos of the students must be recorded from the beginning to the end of theexamination.
All students (whole body) and their activities need to be visible. The IChO2021
Organizer will send the individual Zoom meeting links to invigilators. Invigilators shouldclick on the link at a reasonable time before the examination to directly enter the Zoom
meeting hosted by the IChO2021 Organizer. The recording in the cloud will start
automatically. Invigilators should place their PC or web camera at a location where thewhole room (four students together) can be seen. All devices must have a stableinternet connection and the data-transfer rate must be greater than 2 Mbps.
If a country faces a technical problem regarding a stable internet connection becauseof local factors, it must report the situation to the IChO2021 Organizer before theexamination. In this situation, offline recording of the examination will be approved, andthe invigilators must upload the recorded video data after the examination. If recording
offline, the video-camera or recording device must be able to record at least 5 hours inan easily shared format (e.g. MP4) with a reasonable file size and quality. The
recording can be made in parts without any perceivable time-gaps (e.g. two devices
are used alternatively). The recording file must have time-stamps.
Students or their parents must give their written consent for the recording and its
sharing with the IChO2021 Organizer.
4. Important Dates
9:00 pm JST, 23 July
Online training for Oly-Exam will be held via Zoom.
9:00 am JST, 25 July
The online opening ceremony will start. The access point for the ceremony will beannounced separately. After the opening ceremony, the mentors are not allowed tocontact the students.
9:00 pm JST, 25 July
Oly-Exam will be open for access. The first versions of the problems will be provided to
mentors, who can submit questions, suggestions, corrections and comments via OlyExam. Online discussion will end at 9:00 am JST, 26 July. The Organizing Committee
expects mentors to post all discussions on Oly-Exam to keep the Jury meeting short.

Examination91

53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
9:00 pm JST, 26 July
The first International Jury meeting will be held via Zoom to finalize the problems. The
Zoom meeting link and password will be sent to mentors.
The attendees’ display names should be their Country Code (three letters) followed bytheir name (e.g., JPN_Aaa Bbb). The display name can be changed after entering theZoom meeting.
Only the head mentor can vote in the Jury meeting. When the Jury meeting is split into
two parallel sessions, and the head mentor and mentor attend each session separately,
mentor can also vote.
Observers can attend the Jury meeting, but guests are not allowed. If the display namedoes not match the registered name, the host will dismiss this attendee from the Zoom
meeting after taking care to ensure that only the appropriate people attend the Jury
meeting.
9:00 am JST, 27 July
Translation via Oly-Exam will begin. The official English versions of the problems will
be provided to mentors via Oly-Exam. If any revisions have been made, Oly-Exam willshow the revised version of the problems along with the previous version. The changes
can therefore be readily reflected in the translations by the mentors.
After the translations are completed, the mentors should approve the translated
versions of the problems. Once the mentors approve a translation, no more changes
are allowed. Therefore, approvals must be done carefully. The translations must becompleted by 9:00 am JST, 28 July.
11:00 am JST, 28 July
Invigilators can access Oly-Exam to print out the translated versions of the problems
along with the official English version.
2:00 pm to 12:00 pm JST, 28 July
Invigilators instruct the students to start the examination according to the time schedulein each country.
7:00 pm JST, 28 July to 5:00 am JST, 29 July
Invigilators instruct the students to stop the examination at 5 hours after the start time(i.e. from 2:00 pm to 7:00 pm JST in the earliest timetable and from 12:00 pm to 5:00
am JST in the latest timetable). The invigilators collect all answer sheets, sort and scanthem, and convert them to PDF files. The PDF files for each student are submitted to
Oly-Exam.

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The 53rd IChO 2021 Japan53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
9:00 am JST, 29 July
The student answers, solutions, and marking scheme are provided to mentors via OlyExam. The Organizer and the mentors begin marking.
9:00 am JST, 30 July
Grading of the students will be announced by the Organizer. The mentors decide thearbitration list and report it via Oly-Exam. The deadline for requests will be 9:00 pm
JST, 30 July.
9:00 pm JST, 30 July
The second International Jury meeting will be held via Zoom. This meeting is intended
mainly for IChO business. The time slots for arbitration will be also announced. The
attendees are requested to follow the Zoom meeting rules noted above.
9:00 am JST, 31 July to 12:00 am J ST, 1 August
Arbitration will be conducted via Zoom. The mentors should enter the Zoom meeting forevery problem. Mentors are requested to follow the Zoom meeting rules noted above.
Arbitration time slots will be arranged according to the local time zones of participating
countries.
9:00 am JST, 1 August
The final points scores will be provided to mentors via Oly-Exam.
9:00 pm JST, 2 August
The online closing ceremony will start. Students may attend the ceremony with theiravatars. The access point for the ceremony will be announced via email and thewebsite. Medals and certificates will be sent to the participants via surface mail.
Certificates can also be sent via email.
5. Contact Us
5-1. Technical Support
During the Olympiad period, technical issues should be reported tosupport@icho2021.org. The support team will get back to you as soon as possible.
5-2. Instant Communication
Telegram will be used for text-based and instant announcements. Information on how
to access Telegram will be provided separately. All mentors and invigilators are
expected to download the Telegram application on their mobile device or computer

Examination

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53rd IChO Japan 2021
Chemistry! It’s Cool!
Examination Guideline
before IChO2021 to avoid missing any instant information from the Organizing
Committee. Telegram display names should consist of a Country Code (three letters)
followed by the person’s name (e.g., JPN_Aaa Bbb).

94

The 53rd IChO 2021 Japan

Instruction for Invigilators
1. Training of Oly-ExamThere will be a training session of Oly-Exam for Invigilators via Zoom meeting at
0:00 JST, July 24 (15:00 UTC, July 23):https://zoom.us/j/4189597251?pwd=R3dXQjkremxFNmJaY1BZWFByS0pDdz09
Meeting ID: 418 959 7251
Pass Code: 916970
In this session, following topics will be discussed:
How to access Oly-Exam
How to download the examination problems (both the official English version
and the translated version) and answer sheets
How to submit the scanned pdf files after the examination
2. Information for the examination
Access accounts for Oly-Exam, Zoom ID for on-line recording, and student codes
will be informed after the training session.
The following information should be checked before the examination:
Names of students in all locations of your country
Starting time of the examination in the local time
Brand name and model name of each calculators
3. Communication ban
Students are not allowed to use any electronic communication devices (e.g.,smartphone, computers, smartwatches) during the examination and between
7:00 pm and 12:00 pm JST, 28 July. Invigilators have to control thecommunication ban.
4. Setting of the Location
The examination location should be a calm and quiet room. Please maintain thelocation in a state suitable for the examination.
The students must maintain an appropriate distance from each other in theexamination room.
Invigilators should prepare water and snacks or refreshments for the students.
Basically, they should be outside of the examination room not to disturb otherstudents. However, they can be inside of the room or on the desk if invigilators
can manage the examination room adequately.
The location should have:
Electricity
PC or smartphone with zoom application
Web camera (PC-built-in camera can be used)
Microphone (PC-built-in microphone can be used)High quality printer
1 / 4

Examination

95

-

Scanner with PDF-conversion software
Stable internet connection.

No additional time will be given, even if the examination is interrupted as aresult of local problems. It is strongly recommended that recording, printing,scanning and uploading files are tested before the examination.
5. Equipment
Students can use only:
A non-programmable scientific electronic calculator
Good writing pen with dark ink
A ruler
Students are allowed to put equipment that is necessary for the examination(e.g., medicine and handkerchief) on their desk.
6. Recording
All students (whole body) and their activities during the examination will berecorded via Zoom application.
Invigilators should enter the Zoom meeting hosted by the organizer at areasonable time before the examination. The recording in the cloud will start.
Invigilators should place their PC or web camera at a location where all students
in the location can be viewed.
The location will be inspected by the organizer. Please follow the request of theorganizer who controls the Zoom meeting.
Only for the country that registered Off-line recording: If a country registered
the off-line recording because of local factors, invigilators have to record theexamination as the same manner of on-line recording. The video-camera orrecording device used in off-line recording must be able to record at least 5 hours
in an easily shared format (e.g., MP4) with a reasonable file size, quality, andtime-stamp. The recording can be made in parts without any perceivable timegaps (e.g., two devices are used alternatively). The URL for upload will be
informed separately.

7. Examination-

Invigilators can access Oly-Exam after 9:00 am JST (0:00 am UTC), 28 Julyto download the problems and answer sheets (both the translated and theofficial English version). Invigilators must complete the downloading and theprinting of the both materials (A4 format) for each student before starting
the examination. The problems and answer sheets must be printed clearly on
only one side (the back must be blank). Although some problems include
color figures, color-printing is not essential. The print-out can be boundseparately for each student. Any binding stationary (clip, stapler, binder etc.)
can be used.
Every problem and answer sheets have student codes. If there are more than
one examination locations in the country, carefully prepare the only
2 / 4

96

The 53rd IChO 2021 Japannecessary problems and answer sheets for the location.
-

Please also download and print out the report form from the download site of
Oly-Exam. The report form will be available also from the Web site:
https://www.icho2021.org/problems/icho2021/-

Invigilators may activate Zoom link 30-60 min before the examination toconnect the organizer. The organizers will inform a Zoom link for a country.
If there are more than one examination locations in the country, use thesame link in the country.

-

After Zoom connection is established, the organizer will inspect theexamination room: Name of invigilators and students, the face of students,
the position of camera for recording, distance between students, calculator,
etc.

-

After the inspection, the organizer will be invisible, although the organizer
will be always there. Please do not mute. Please do not stop video. To
maintain the examination room calm, the volume can be minimized.

-

Invigilators should clearly announce the examination timetable to thestudents before the examination. Invigilators must not allow the students toopen the booklet of problems before the examination starts.

-

At least 5 min before the starting time, invigilators allow the students toread the General Instruction at the first page.

-

At the exact starting time registered, invigilators have to instruct thestudents to start the examination. All locations in the country must follow
the same examination timetable.

-

Students are not supposed to ask questions during the exam. Invigilators are
not to speak with students other than to issue the instructions to begin andend the examination. Students may request the break for bathroom, water,and snacks, and may view the official English version of the examination
only when they clarification of a problem.

-

The details of the examination (printing time, starting time, ending time,scanning time, and times and length of bathroom breaks) must be recorded
by invigilators.

-

Invigilators announce the warning at 30 min before the end time (4 hours
and 30 min after the start time).

-

Invigilators instruct the students to stop the examination at 5 hours after
the start time. All students have to stop working. If students do not stop
writing, warn the nullification of the points.

-

After the examination, invigilators collect all answer sheets, sort the sheetsin the order of the page numbers, and scan them to prepare one PDF file per
problem and per student. The PDF files for each student are submitted toorganizer using Oly-Exam within 2 hours after the end of the examination.
The answer sheets must be scanned clearly and properly. Even blank answer
3 / 4

Examination97

sheets must be uploaded.
All process must be confidential, and invigilator must keep the students
away from the answer sheets after the examination.

4 / 4

98

The 53rd IChO 2021 Japan

Problem English Version
with Solution

IChO

G0-1
English (Official)

International Chemistry
International
ChemistryOlympiad
Olympiad2021
2021 Japan
53rd
IChO2021
The 53rd
IChO Japan
2021 Japan
25th
25th July
July –- 2nd
2nd August,August, 2021
2021
https://www.icho2021.org
https://www.icho2021.org

Examination

101

IChO

G0-2
English (Official)

General Instruction• You are allowed to use only pen to write the answer.
• Your calculator must be non-programmable.
• This examination has 9 problems.
• You can solve the problems in any order.
• You will have 5 hours to solve all problems.
• You can begin working only after the START command is given.
• All results must be written in the appropriate answer boxes with pen on the answer sheets. Use
the back of the question sheets if you need scratch paper. Remember that answers written outside
the answer boxes will not be graded.
• Write relevant calculations in the appropriate boxes when necessary. Full marks will be given forcorrect answers only when your work is shown.
• The invigilator will announce a 30-minute warning before the STOP command.
• You must stop working when the STOP command is given. Failure to stop writing will lead to thenullification of your examination.
• The official English version of this examination is available on request only for clarification.
• You are not allowed to leave your working place without permission. If you need any assistance(broken calculator, need to visit a restroom, etc), raise your hand and wait until an invigilator arrives.
GOOD LUCK!

Problems and Grading Information
Title

102

Total Score

Percentage

1

Hydrogen at a Metal Surface

24

11

2

Isotope Time Capsule

35

11

3

Lambert–Beer Law?

22

8

4

The Redox Chemistry of Zinc

32

11

5

Mysterious Silicon

60

12

6

The Solid-State Chemistry of Transition Metals

45

13

7

Playing with Non-benzenoid Aromaticity

36

13

8

Dynamic Organic Molecules and Their Chirality

26

11

9

Likes and Dislikes of Capsules

23

10

Total

100

The 53rd IChO 2021 Japan

IChO

G0-3
English (Official)

Physical Constants and Equations
Constants
Speed of light in vacuum

𝑐𝑐 𝑐 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑐 𝑐𝑐8 m s−1

Planck constantℎ = 6.62607015×10−34 J s

Elementary charge

𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒−19 C

Electron mass𝑚𝑚e =9.10938370×10−31 kg

Electric constant(permittivity of vacuum)

𝜀𝜀0 =8.85418781×10−12 F m−1

Avogadro constant

𝑁𝑁A = 6.02214076 ×1023 mol−1

Boltzmann constant𝑘𝑘B =1.380649×10−23 J K−1

Faraday constant

𝐹𝐹 𝐹𝐹𝐹A × 𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒4 C mol−1

Gas constant

𝑅𝑅 𝑅𝑅𝑅A × 𝑘𝑘B =8.31446261815324 J K−1 mol−1=8.2057366081×10−2 L atm K−1 mol−1

Unified atomic mass unit

𝑢𝑢 𝑢𝑢 Da =1.66053907×10−27 kg

Standard pressure

𝑝𝑝 𝑝𝑝 bar =105 Pa

Atmospheric pressure

𝑝𝑝atm =1.01325×105 Pa

Zero degree Celsius

0 ∘ C =273.15 KÅngstrom

1 Å =10−10 m

Picometer

1 pm =10−12 m

Electronvolt

1 eV =1.602176634×10−19 J

Part-per-million

1 ppm =10−6

Part-per-billion

1 ppb =10−9

Part-per-trillion

1 ppt =10−12pi𝜋𝜋 𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋𝜋The base of the natural logarithm(Euler's number)𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒

Examination

103

IChO

G0-4
English (Official)

Equations
The ideal gas law

Coulomb's law

𝑃𝑃 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃𝑃, where 𝑃𝑃 is the pressure, 𝑉𝑉 is the volume, 𝑛𝑛 is the amount of substance,
𝑇𝑇 is the absolute temperature of ideal gas.
𝑞𝑞 𝑞𝑞
𝐹𝐹 𝐹 𝐹𝐹e 1 2 2
𝑟𝑟, where 𝐹𝐹 is the electrostatic force, 𝑘𝑘e (≃ 9.0 × 109 N m2 C−2 ) is Coulomb's
constant, 𝑞𝑞1 and 𝑞𝑞2 are the magnitudes of the charges, and 𝑟𝑟 is the distance
between the charges.

The first law of thermodynamicsΔ𝑈𝑈 𝑈𝑈𝑈 𝑈 𝑈𝑈
, where Δ𝑈𝑈 is the change in the internal energy, 𝑞𝑞 is the heat supplied, 𝑤𝑤is the work done.

Enthalpy 𝐻𝐻

𝐻𝐻 𝐻𝐻𝐻𝐻𝐻𝐻𝐻𝐻

Entropy based on Boltzmann's principle 𝑆𝑆

𝑆𝑆 𝑆𝑆𝑆B ln 𝑊𝑊, where 𝑊𝑊 is the number of microstates.
𝑞𝑞
Δ𝑆𝑆 𝑆 rev𝑇𝑇, where 𝑞𝑞rev is the heat for the reversible process.

The change of entropy
Δ𝑆𝑆
Gibbs free energy 𝐺𝐺

𝐺𝐺 𝐺𝐺𝐺𝐺𝐺𝐺𝐺𝐺
Δr 𝐺𝐺∘ = −𝑅𝑅𝑅𝑅 ln 𝐾𝐾 𝐾𝐾𝐾𝐾𝐾𝐾 𝐾𝐾 ∘, where 𝐾𝐾 is the equilibrium constant, 𝑧𝑧 is the number of electrons, 𝐸𝐸 ∘ isthe standard electrode potential.

Reaction quotient 𝑄𝑄

Δr 𝐺𝐺 𝐺𝐺r 𝐺𝐺∘ +𝑅𝑅𝑅𝑅 ln 𝑄𝑄
For a reaction
𝑎𝑎A + 𝑏𝑏B ⇌ 𝑐𝑐C + 𝑑𝑑D𝑐𝑐
𝑑𝑑[C] [D]
𝑄𝑄 𝑄
𝑎𝑎𝑏𝑏[A] [B], where [A] is the concentration of A.

104

The 53rd IChO 2021 Japan

IChO

G0-5
English (Official)

Heat change Δ𝑞𝑞
Nernst equation for redox reaction
Arrhenius equation

Δ𝑞𝑞 𝑞 𝑞𝑞𝑞𝑞m Δ𝑇𝑇, where 𝑐𝑐m is the temperature-independent molar heat capacity.
𝑅𝑅𝑅𝑅
𝐶𝐶
𝐸𝐸 𝐸 𝐸𝐸 ∘ +
ln ox
𝑧𝑧𝑧𝑧
𝐶𝐶red
, where 𝐶𝐶ox is the concentration of oxidized substance, 𝐶𝐶red is the concentration of reduced substance.
𝐸𝐸
𝑘𝑘 𝑘 𝑘𝑘 exp (− 𝑎𝑎 )𝑅𝑅𝑅𝑅
, where 𝑘𝑘 is the rate constant, 𝐴𝐴 is the pre-exponential factor, 𝐸𝐸𝑎𝑎 is theactivation energy.
exp(𝑥𝑥𝑥 𝑥 𝑥𝑥𝑥𝑥

Lambert–Beer equation

𝐴𝐴𝐴 𝐴𝐴𝐴𝐴𝐴𝐴, where 𝐴𝐴 is the absorbance, 𝜀𝜀 is the molar absorption coefficient, 𝑙𝑙 is the
optical path length, 𝑐𝑐 is the concentration of the solution.

Henderson–Hasselbalch
equation

For an equilibrium
HA ⇌ H+ + A−
, where equilibrium constant is 𝐾𝐾a ,[A− ])pH = p𝐾𝐾a + log ([HA]
𝑐𝑐
𝐸𝐸 𝐸 𝐸𝐸𝐸 𝐸 𝐸
𝜆𝜆, where 𝜈𝜈 is the frequency, 𝜆𝜆 is the wavelength of the light.

Energy of a photon
The sum of a geometricseriesWhen 𝑥𝑥 𝑥 𝑥,

Approximation equationthat can be used to solve
problems

When 𝑥𝑥 𝑥 𝑥,
1
≃ 1 + 𝑥𝑥
1 − 𝑥𝑥

𝑛𝑛

1 + 𝑥𝑥 𝑥 𝑥𝑥2 + ⋯ + 𝑥𝑥𝑛𝑛 = ∑𝑖𝑖𝑖𝑖 𝑥𝑥𝑖𝑖 =1 − 𝑥𝑥𝑛𝑛𝑛𝑛
1 − 𝑥𝑥Examination

105

IChO

G0-6
English (Official)

Periodic Table106

The 53rd IChO 2021 Japan

IChO

G0-7
English (Official)

1

H NMR Chemical ShiftsΔ𝛿𝛿 for one alkyl group-substitution: ca. +0.4 ppm
Examination

107

Q1-1

IChO

English (Official)Hydrogen at a Metal Surface
11 % of the total
Question

A.1

A.2

B.1

B.2

B.3

B.4

Total

Points

6

4

5

3

3

3

24

Score

Hydrogen is expected to be a future energy source that does not depend on fossil fuels. Here, we willconsider the hydrogen-storage process in a metal, which is related to hydrogen-transport and -storage
technology.

Part AAs hydrogen is absorbed into the bulk of a metal via its surface, let us first consider the adsorption
process of hydrogen at the metal surface, H2 (g) → 2H(ad), where the gaseous and adsorbed states ofhydrogen are represented as (g) and (ad), respectively. Hydrogen molecules (H2 ) that reach the metal
surface (M) dissociate at the surface and are adsorbed as H atoms (Fig. 1). Here, the potential energyof H2 is represented by two variables: the interatomic distance, 𝑑𝑑, and the height relative to the surface
metal atom, 𝑧𝑧. It is assumed that the axis along the two H atoms is parallel to the surface and that thecenter of gravity is always on the vertical dotted line in Fig. 1. Fig. 2 shows the potential energy contour
plot for the dissociation at the surface. The numerical values represent the potential energy in units ofkJ per mole of H2 . The solid line spacing is 20 kJ mol−1 , the dashed line spacing is 100 kJ mol−1 , and thespacing between solid and dashed lines is 80 kJ mol−1 . The zero-point vibration energy is ignored.

108

The 53rd IChO 2021 Japan

Q1-2

IChO

English (Official)

Fig.1 Definition of variables. Drawing is not in scale.

Fig.2

Examination

109

Q1-3

IChO

English (Official)

A.1

For each of the following items (i)–(iii), select the closest value from A–G.
(i) The interatomic distance for a gaseous H2 molecule(ii) The interatomic distance between metal atoms (𝑑𝑑M in Fig. 1)(iii) The distance of adsorbed H atoms from the surface (ℎad in Fig. 1)
A. 0.03 nm

B. 0.07 nm

C. 0.11 nm

E. 0.19 nm

F. 0.23 nm

G. 0.27 nm

6pt

D. 0.15 nm(i) B (ii) F (iii) A
6 points in total:
2 point for (i), (ii) and (iii)A.2

For each of the following items (i)–(ii), select the closest value from A–H.
(i) the energy required for the dissociation of gaseous H2 to gaseous H[H2 (g) → 2H(g)](ii) the energy released during the adsorption of a gaseous H2 [H2 (g) → 2H(ad)]A. 20 kJ mol−1

B. 40 kJ mol−1

C. 60 kJ mol−1

D. 100 kJ mol−1

E. 150 kJ mol

F. 200 kJ mol

G. 300 kJ mol

H. 400 kJ mol−1

−1

−1

−1

4pt

(i) H (ii) D
4 points in total:
2 points for (i) and (ii)Part B
The adsorbed hydrogen atoms are then either absorbed into the bulk, or recombine and desorb backinto the gas phase, as shown in the reactions (1a) and (1b). H(ab) represents a hydrogen atom absorbed
in the bulk.

The reaction rates per surface site for adsorption, desorption, and absorption are 𝑟𝑟1 [s−1 ], 𝑟𝑟2 [s−1 ] and𝑟𝑟3 [s−1 ] , respectively. They are expressed as:

110

The 53rd IChO 2021 Japan

Q1-4

IChO

English (Official)where 𝑘𝑘1 [s−1 Pa−1 ], 𝑘𝑘2 [s−1 ] and 𝑘𝑘3 [s−1 ] are the reaction rate constants and 𝑃𝑃H2 is the pressure of H2 .
Among the sites available on the surface, 𝜃𝜃 (0 ≤ 𝜃𝜃 𝜃 𝜃) is the fraction occupied by H atoms. It is assumed
that adsorption and desorption are fast compared to absorption (𝑟𝑟1 , 𝑟𝑟2 ≫ 𝑟𝑟3 ) and that 𝜃𝜃 remains constant.
B.1

𝑟𝑟3 can be expressed as:

5pt

Express 𝐶𝐶 using 𝑘𝑘1 and 𝑘𝑘2 .
From 𝑟𝑟1 , 𝑟𝑟2 ≫ 𝑟𝑟3 and 𝑟𝑟1 = 𝑟𝑟2 + 𝑟𝑟3 ,𝑟𝑟1 = 𝑟𝑟2 .
Then 𝑘𝑘1 𝑃𝑃H2 (1 − 𝜃𝜃𝜃2 = 𝑘𝑘2 𝜃𝜃2 (1')
Solve for 𝜃𝜃:
1
𝜃𝜃 𝜃
(2')
𝑘𝑘2
1+√
𝑃𝑃H2 𝑘𝑘1
From 𝑟𝑟3 = 𝑘𝑘3 𝜃𝜃 𝜃
𝑘𝑘3
𝑟𝑟3 =
𝑘𝑘
1+√ 2
𝑃𝑃H2 𝑘𝑘1
𝑘𝑘Thus, 𝐶𝐶 𝐶 1
𝑘𝑘2
5 points in total:
5 points for the final correct answer.
partial points:(1′) and (2′): 2 points each.
A metal sample with a surface area of 𝑆𝑆 𝑆𝑆𝑆𝑆 𝑆 𝑆𝑆−3 m2 was placed in a container (1L = 1.0 ×10−3 m3 )with H2 (𝑃𝑃H2 = 1.0 ×102 Pa ). The density of hydrogen-atom adsorption sites on the surface was 𝑁𝑁 𝑁
1.3 ×1018 m−2 . The surface temperature was kept at 𝑇𝑇 𝑇 𝑇𝑇𝑇 K. As the reaction (1) proceeded, 𝑃𝑃H2
decreased at a constant rate of 𝑣𝑣 𝑣𝑣𝑣𝑣𝑣𝑣𝑣−4 Pa s−1 . Assume that H2 is an ideal gas and that the volumeof the metal sample is negligible.

Examination

111

Q1-5

IChO

English (Official)

B.2

Calculate the amount of H atoms in moles absorbed per unit area of the surface
per unit time, 𝐴𝐴 𝐴mol s−1 m−2 ].

3pt

The change in the amount of hydrogen atoms per unit time in the gas phase is 𝐴𝐴 𝐴 𝐴𝐴. Thus,
2𝑣𝑣𝑣𝑣
𝐴𝐴 𝐴 𝐴𝐴 𝐴(1')
𝑅𝑅𝑅𝑅
1.0 × 10−3
= 2.4 × 10−10 mol s−1= 2 × 4.0 × 10−4 ×
8.31 × 400
Therefore,
𝐴𝐴 𝐴 𝐴𝐴𝐴 𝐴 𝐴𝐴−7 mol s−1 m−2
3 points in total:
2 points for (1'), and 1 point for the final answer.
𝑣𝑣𝑣𝑣-1 point if 𝐴𝐴 𝐴 𝐴𝐴 𝐴
(missing the factor 2).
𝑅𝑅𝑅𝑅
B.3

112

At 𝑇𝑇𝑇 400 K, 𝐶𝐶 equals 1.0 × 102 Pa−1 . Calculate the value of 𝑘𝑘3 at 400 K. If you
did not obtain the answer to B.2, use 𝐴𝐴 𝐴 𝐴𝐴𝐴 𝐴 𝐴𝐴−7 mol s−1 m−2 .

The 53rd IChO 2021 Japan

3pt

Q1-6

IChO

English (Official)

The relationship between 𝑟𝑟3 and 𝐴𝐴 is:
𝑁𝑁
𝐴𝐴 𝐴 𝐴𝐴3 ×
𝑁𝑁A
Thus,
𝑁𝑁
𝑟𝑟3 = 𝐴𝐴 𝐴 A = 1.1 × 10−1 s−1 (1')
𝑁𝑁
Solution 1
𝑘𝑘3
𝑟𝑟3 =
1+√

𝑘𝑘2
𝑃𝑃H2 𝑘𝑘1

=

𝑘𝑘3
1+√

1
10000

=

𝑘𝑘3
(2')
1.01

Thus,
𝑘𝑘3 = 1.01 × 𝑟𝑟3 = 1.1 × 10−1 s−1
Solution 2
Under the condition 𝑃𝑃H2 𝐶𝐶 𝐶 𝐶𝐶 it follows that:
𝑘𝑘3
𝑘𝑘
𝑟𝑟3 =
≈ 3 = 𝑘𝑘3 (3')
1
𝑘𝑘
1+√ 2
𝑃𝑃H2 𝑘𝑘1Thus,
𝑘𝑘3 = 𝑟𝑟3 = 1.1 × 10−1 s−1(1.7 × 10−1 s−1 with 𝐴𝐴 𝐴 𝐴𝐴𝐴 𝐴𝐴𝐴−7 mol s−1 m−2 )3 points in total:
2 points for the correct value (1').
(if correct formulation (1'), 1 point).
1 point for the final correct answer.
It does not affect the score whether the approximation of (3′) is used or not.
B.4

At a different 𝑇𝑇 , 𝐶𝐶 𝐶 𝐶𝐶𝐶 𝐶𝐶𝐶3 Pa−1 and 𝑘𝑘3 = 4.8 × 10−2 s−1 are given. For 𝑟𝑟3 as afunction of 𝑃𝑃H2 at this temperature, select the correct plot from (a)–(h).

3ptExamination

113

IChO

Q1-7
English (Official)

The figures show the region in which 𝑃𝑃H2 𝐶𝐶 𝐶 𝐶. Therefore,
𝑘𝑘3
(1')
𝑟𝑟3 =
1
1+√
𝑃𝑃H2 𝐶𝐶𝑘𝑘3≈= 𝑘𝑘3 √𝑃𝑃H2 𝐶𝐶 𝐶 𝐶𝐶𝐶√𝑃𝑃H2
1√
𝑃𝑃H2 𝐶𝐶Thus, (b)3 points in total:
3 points for selecting (b).

114

The 53rd IChO 2021 Japan

Q2-1

IChO

English (Official)

Isotope Time Capsule
11 % of the total
Question

A.1

A.2

A.3

A.4

Total

Points

8

8

10

9

35

Score

Molecular entities that differ only in isotopic composition, such as CH4 and CH3 D, are called isotopologues. Isotopologues are considered to have the same chemical characteristics. In nature, however,there exists a slight difference.
Assume that all of the substances shown in this Question are in a gas phase.
Let us consider the following equilibrium:

The entropy, 𝑆𝑆, increases with increasing the number of possible microscopic states of a system, 𝑊𝑊 :𝑊𝑊 𝑊 𝑊 for 12 C16 O2 and 12 C18 O2 . In contrast, 𝑊𝑊 𝑊 𝑊 for a 12 C16 O18 O molecule because the oxygen atoms
are distinguishable in this molecule. As the right-hand side of the equilibrium shown in eq. 1 has two
12 16 18
C O O molecules, 𝑊𝑊 𝑊 𝑊2 = 4.

Examination

115

Q2-2

IChO

English (Official)

A.1

The enthalpy change, Δ𝐻𝐻, of eq. 3 is positive regardless of the temperature.

8pt

Calculate the equilibrium constants, 𝐾𝐾, for eq. 3 at very low (think of 𝑇𝑇 𝑇 𝑇) andvery high (think of 𝑇𝑇 𝑇 𝑇𝑇) temperatures. Assume that the reaction remains
unchanged at these temperatures and that Δ𝐻𝐻 converges to a constant value
for high temperatures.

Δ𝐺𝐺∘ = Δ𝐻𝐻 ∘ − 𝑇𝑇 𝑇𝑇𝑇 ∘ = −𝑅𝑅𝑅𝑅 ln 𝐾𝐾 𝐾 ln 𝐾𝐾 𝐾𝐾(𝐾𝐾 𝐾 exp [−

Δ𝐻𝐻 ∘
Δ𝑆𝑆 ∘
] exp [
])
𝑅𝑅𝑅𝑅
𝑅𝑅

Δ𝐻𝐻 ∘
Δ𝑆𝑆 ∘
+
𝑅𝑅𝑅𝑅
𝑅𝑅

𝑇𝑇 𝑇 𝑇: As Δ𝐻𝐻 ∘ > 0, ln 𝐾𝐾 converges to −∞ and therefore 𝐾𝐾 𝐾𝐾.
Δ𝑆𝑆 ∘𝑇𝑇 𝑇 𝑇𝑇: ln 𝐾𝐾 𝐾
𝑅𝑅Given that Δ𝑆𝑆 ∘ per 1 mole is 𝑁𝑁A 𝑘𝑘B ln 𝑊𝑊 𝑊𝑊𝑊 ln 2, 𝐾𝐾 𝐾𝐾.
8 points in total:
3 points for the correct answer for 𝑇𝑇 𝑇 𝑇,
5 points for the correct answer for 𝑇𝑇 𝑇 𝑇𝑇.
Partial points:
If neither the correct answer for 𝑇𝑇 𝑇 𝑇 nor that for 𝑇𝑇 𝑇 𝑇𝑇 is obtained: 2 points for showing that
Δ𝐻𝐻 ∘
Δ𝑆𝑆 ∘
ln 𝐾𝐾 𝐾𝐾
+
.
𝑅𝑅𝑅𝑅
𝑅𝑅
If the correct answer for 𝑇𝑇 𝑇 𝑇𝑇 is not obtained: 2 points for showing that 𝑊𝑊 𝑊𝑊.
The ΔH of the following process can be explained by molecular vibrations.

At 𝑇𝑇 = 0 K, the vibrational energy of a diatomic molecule whose vibration frequency is 𝜈𝜈 𝜈s−1 ] is expressedas:Wherein 𝑘𝑘 is the force constant and 𝜇𝜇 the reduced mass, which is expressed in terms of the mass of thetwo atoms in the diatomic molecule, 𝑚𝑚1 and 𝑚𝑚2 , according to:116

The 53rd IChO 2021 Japan

Q2-3

IChO

English (Official)

A.2

The vibration of H2 is at 4161.0 cm−1 when reported as a wavenumber.
Calculate the Δ𝐻𝐻 of the following equation at 𝑇𝑇 = 0 K in units of J mol−1 .

8pt

Assume that:• only the vibrational energy contributes to the Δ𝐻𝐻.
• the 𝑘𝑘 values for H2 , HD, and D2 are identical.
• the mass of H to be 1 Da and the mass of D to be 2 Da.
𝜇𝜇H2 = 1/2 Da, 𝜇𝜇HD = 2/3 Da, 𝜇𝜇D2 = 1 Da.
𝜇𝜇H
𝜇𝜇H
𝜈𝜈D
𝑘𝑘 𝜈𝜈
1
√ , HD = √ 2 and 2 = √ 2 are obtained.
Using 𝜈𝜈 𝜈
2𝜋𝜋 𝜇𝜇 𝜈𝜈H2
𝜇𝜇HD
𝜈𝜈H2
𝜇𝜇D2
The frequency of the H2 vibration is 4161.0 cm−1 in units of wavenumbers.
Therefore, the frequencies of the molecular vibration for HD and D2 are calculated to be 3603.5 cm−1
and 2942.3 cm−1 , respectively.
The difference of the zero-point energies of eq. 4 is calculated to be(4161.0 + 2942.3)/2 − 3603.5 = −51.9 cm–1 .
𝐸𝐸 𝐸 𝐸𝐸A ℎ𝜈𝜈 𝜈𝜈𝜈A ℎ𝑐𝑐𝑐𝑐 𝑐 (𝜈𝜈:̃ frequency in wavenumbers), and therefore 𝐸𝐸 𝐸𝐸𝐸𝐸 ∘ = −621 J mol−1 .
8 points in total:
2 points for the correct vibrational frequency of HD(1 point for the correct 𝜇𝜇 value of HD,𝜇𝜇H
𝜈𝜈
1 point for the correct formulation ( HD = √ 2 ) to calculate the vibrational frequency of HD),
𝜈𝜈H2
𝜇𝜇HD
2 points for the correct vibrational frequency of D2(1 point for the correct 𝜇𝜇 value of D2 ,𝜈𝜈D𝜇𝜇H
1 point for the correct formulation ( 2 = √ 2 ) to calculate the vibrational frequency of D2 ),
𝜈𝜈H2
𝜇𝜇D2
2 points for the correct conversion from cm−1 to J mol−1(partial points: 1 point for the correct conversion from cm−1 to J (𝑁𝑁A is missing)),
2 points for the correct energy difference(partial points: -1 point when the value is not divided by 2, -1 point when the sign is wrong).

Examination

117

Q2-4

IChO

English (Official)

The molar ratio of H2 , HD, and D2 depends on the temperature in a system in equilibrium. Here, ΔD2 isdefined as the change of the molar ratio of D2 .

[D2 ]
[D ]
in the sample and 𝑅𝑅D∗ 2 to 2 at 𝑇𝑇 𝑇 𝑇𝑇. It should be noted here that the
[H2 ]
[H2 ]
distribution of isotopes becomes random at 𝑇𝑇 𝑇 𝑇𝑇.

Here, 𝑅𝑅D2 refers to
A.3

118

Calculate ΔD2 with natural D abundance when the isotopic exchange is in equilibrium at the temperature where 𝐾𝐾 in eq. 4 is 0.300. Assume that the naturalabundance ratios of D and H are 1.5576 × 10–4 and 1 − 1.5576 × 10–4 , respectively.

The 53rd IChO 2021 Japan

10pt

Q2-5

IChO

English (Official)

Let the sum of the concentrations of H2 , HD, and D2 be 𝐶𝐶.
Solution 1:
𝑇𝑇 𝑇 𝑇𝑇 𝑇𝑇𝑇 𝑇 𝑇𝑇𝑇𝑇 𝑇[H2 ]0 =(1 − 1.5576 × 10−4 )2 𝐶𝐶 𝐶 𝐶𝐶𝐶𝐶𝐶𝐶 𝐶𝐶𝐶−1 𝐶𝐶[D2 ]0 =(1.5576 × 10−4 )2 𝐶𝐶 𝐶 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶−8 𝐶𝐶𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾Let the amount of change in the molar ratio be 𝑥𝑥.
( [H𝐶𝐶2 ]0 + 𝑥𝑥𝑥 𝑥 [D𝐶𝐶2 ]0 + 𝑥𝑥𝑥[H2 ][D2 ]
=
=𝐾𝐾
2
2
0
[HD]
( [HD]−
2𝑥𝑥𝑥
𝐶𝐶
Solve the equation for 𝑥𝑥 when 𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾:[HD]20
[H ]
[D ]
[HD]0
[H ] [D ]) = 0,) 𝑥𝑥 𝑥𝑥 2 0 2 2 0 − 𝐾𝐾
(1 − 4𝐾𝐾𝐾𝐾𝐾2 + ( 2 0 + 2 0 +4𝐾𝐾
𝐶𝐶
𝐶𝐶
𝐶𝐶
𝐶𝐶
𝐶𝐶 2
𝑥𝑥 𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥−9 .
From this value, we obtain [H2 ] =9.9969 × 10−1 𝐶𝐶 and [D2 ] =2.9112 × 10−8 𝐶𝐶.
2.9112×10−8
𝑅𝑅D2−1
ΔD2 = ∗ − 1= 9.9969×10−8 − 1= 0.200
2.4261×10
𝑅𝑅D2
9.9969×10−1

Solution 2:
By using an appropriate approximation, we can obtain the answer without calculating the concentration of each species.
Let the increase of [D2 ] be 𝛿𝛿.
([H2 ]0 + 𝛿𝛿𝛿𝛿𝛿D2 ]0 + 𝛿𝛿𝛿[H2 ]0 ([D2 ]0 + 𝛿𝛿𝛿[H2 ]0 [D2 ][H ][D ]𝐾𝐾𝐾 2 22 =
≃
=
2
2
2
([HD]
−
2𝛿𝛿𝛿
[HD]
[HD]
[HD]
0

ΔD2 =

𝑅𝑅D2
− 1=
𝑅𝑅D∗ 2[D2 ][H2 ][D2 ]0[H2 ]0[H2 ]0 [D2 ]

−1≃

0

0

[D2 ]
0.300
− 1= [H ] [D ] − 1 ≃− 1= 0.200
22
00[D2 ]0
0.250
2
2
[HD]0

[HD]0

10 points in total:
1 point for the correct [H2 ]0 ,1 point for the correct [D2 ]0 ,2 points for the correct formulation for either [H2 ] or [D2 ],2 points for the correct [H2 ],2 points for the correct [D2 ],and 2 points for the correct ΔD2 .
Full marks when the correct ΔD2 is shown using an appropriate approximation (without calculatingeach concentration).
Partial points: 5 points for showing that [H2 ]0 ≃ [H2 ].
No deficiency point when the sum of the concentration, 𝐶𝐶, is assumed to be 1.

Examination

119

Q2-6

IChO

English (Official)

In general, the molar ratio of the doubly substituted isotopologue, which contains two heavy isotope
atoms in one molecule, increases with decreasing temperature. Let us consider the molar ratio of CO2
molecules with molecular weights of 44 and 47, which are described as CO2 [44] and CO2 [47] below. The
quantity Δ47 is defined as:[CO2 [47]][CO2 [47]]∗toin the sample and 𝑅𝑅47
at 𝑇𝑇 𝑇 𝑇𝑇. The natural abundances of carbon[CO2 [44]][CO2 [44]]and oxygen atoms are shown below; ignore isotopes that are not shown here.

𝑅𝑅47 refers to12

natural abundance

16

natural abundanceC

130.988888

0.011112

C

O

17

O

18

0.997621

0.0003790

0.0020000

O

The temperature dependence of Δ47 is determined as follows, where 𝑇𝑇 is given as the absolute temperature in units of K:

A.4

120

The 𝑅𝑅47 of fossil plankton obtained from the Antarctic seabed was 4.50865×10–5 .
Estimate the temperature using this 𝑅𝑅47 . This temperature is interpreted as the
air temperature during the era in which the plankton lived. Consider only themost common isotopologue of CO2 [47] for the calculation.

The 53rd IChO 2021 Japan

9pt

IChO

Q2-7
English (Official)

The most common isotopologue of CO2 [47] is 13 C16 O18 O.
The molar ratio of 13 C16 O18 O in the case where all the isotopes are distributed randomly is:
0.011112 × 0.002000 × 0.997621 × 2 [O is distinguishable] = 4.43423 × 10−5
The molar ratio of 12 C16 O2 (CO2 [44]) in the case where all the isotopes are distributed randomly is:0.988888 × 0.9976212 = 9.84188 × 10−1
4.43423 × 10−5∗
𝑅𝑅47=
= 4.50547 × 10−59.84188 × 10−1
Δ47 = 7.06 × 10−4
𝑇𝑇 𝑇𝑇𝑇𝑇 K.
9 points in total:
2 points by indicating that the most common isotopologue of CO2 [47] is 13 C16 O18 O.
3 points for the correct molar ratio of 13 C16 O18 O (1 point when ×2 is missing),
2 points for the correct molar ratio of 12 C16 O2 ,2 points for the correct 𝑇𝑇 .
(1 deficiency point when the calculated 𝑇𝑇 is a negative value.)

Examination

121

Q3-1

IChO

English (Official)

Lambert–Beer Law?
8 % of the total
Question

A.1

B.1

B.2

Total

Points

10

6

6

22

Score

In this problem, ignore the absorption of the cell and the solvent. The temperatures of all solutions andgases are kept constant at 25 °C.

Part A
An aqueous solution X was prepared using HA and NaA. The concentrations [A− ], [HA], and [H+ ] in solution X are 1.00 × 10−2 mol L−1 , 1.00 × 10−3 mol L−1 , and 1.00 × 10−4 mol L−1 , respectively, which arecorrelated via the following acid-base equilibrium:
HA ⇌ A− + H+

𝐾𝐾 𝐾

[A− ][H+ ]
[HA]

(1)

The optical path length is 𝑙𝑙 in Part A. Ignore the density change upon dilution. Assume that no chemical
reactions other than eq 1 occur.

122

The 53rd IChO 2021 Japan

Q3-2

IChO

English (Official)

A.1

The absorbance of X was 𝐴𝐴1 at a wavelength of 𝜆𝜆1 . Then, solution X was diluted
to twice its initial volume using hydrochloric acid with pH = 2.500. After the
dilution, the absorbance was still 𝐴𝐴1 at 𝜆𝜆1 . Determine the ratio 𝜀𝜀HA /𝜀𝜀A− , where
𝜀𝜀HA and 𝜀𝜀A− represent the absorption coefficients of HA and of A− , respectively,at 𝜆𝜆1 .

10pt[A− ][H+ ](1.00 × 10−2 )(1.00 × 10−4 )= 1.00 × 10−3 mol L−1=[HA]
1.00 × 10−3
Concentration before the dilution:[HA] = 1.00 × 10−3 mol L−1[A− ] = 1.00 × 10−2 mol L−1[H+ ] = 1.00 × 10−4 mol L−1
𝐾𝐾 𝐾

Concentrations just after the dilution (nominal initial concentrations before the equilibrium):[HA] = 5.00 × 10−4 mol L−1[A− ] = 5.00 × 10−3 mol L−1
1.00 × 10−4 + 3.16 × 10−3
[H+ ] =
= 1.63 × 10−3 mol L−1
2(pH = 2.500 → [H+ ] = 3.16 × 10−3 mol L−1 )Equilibrium after the dilution:[A− ][H+ ](5.00 × 10−3 − 𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥−3 − 𝑥𝑥𝑥== 1.00 × 10−3 mol L−1[HA]
5.00 × 10−4 + 𝑥𝑥
Solve the equation for 𝑥𝑥: 𝑥𝑥 𝑥𝑥𝑥𝑥𝑥 𝑥𝑥𝑥−3 mol L−1→ [A− ] = 3.81 × 10−3 mol L−1 , [HA] = 1.69 × 10−3 mol L−1 .
Therefore,
1.00 × 10−2 𝜀𝜀A− + 1.00 × 10−3 𝜀𝜀HA = 3.81 × 10−3 𝜀𝜀A− + 1.69 × 10−3 𝜀𝜀HA
By solving this equation: 𝜀𝜀HA /𝜀𝜀A− =9.0
10 points in total:
2 points for the correct 𝐾𝐾 value,
2 points for the formulation to give the correct [A− ] and [HA] values after dilution,
2 points for the correct [A− ] and [HA] values after dilution (1 point for each),
2 points for the formulation to give the correct relationship between 𝜀𝜀A− and 𝜀𝜀HA using [A− ] and [HA],
and 2 points for the correct relationship between 𝜀𝜀A− and 𝜀𝜀HA .

Examination

123

Q3-3

IChO

English (Official)Part BLet us consider the following equilibrium in the gas phase.
D ⇌ 2M(2)

Pure gas D is filled into a cuboid container that has a transparent movable wall with a cross-section of 𝑆𝑆(see the figure below) at a pressure 𝑃𝑃 , and equilibrium is established while the total pressure is kept at 𝑃𝑃 .
The absorbance of the gas is 𝐴𝐴 𝐴 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝐴, where 𝜀𝜀, 𝑛𝑛, 𝑉𝑉 , and 𝑙𝑙 are the absorption coefficient, amount of
the gas in moles, volume of the gas, and optical path length, respectively. Assume that all componentsof the gas mixture behave as ideal gases.

Use the following definitions if necessary.
Initial state
D

M

D

M

Partial pressure

𝑃𝑃

0

𝑝𝑝D

𝑝𝑝M

Amount in moles

𝑛𝑛0

0

𝑛𝑛D

𝑛𝑛M

Volume124

After equilibrium

The 53rd IChO 2021 Japan

𝑉𝑉0

𝑉𝑉

Q3-4

IChO

English (Official)

B.1

The absorbance of the gas at 𝜆𝜆B1 measured from direction 𝑥𝑥 (𝑙𝑙 𝑙 𝑙𝑙𝑥𝑥 ) was 𝐴𝐴B1
both at the initial state and after the equilibrium. Determine the ratio 𝜀𝜀D /𝜀𝜀M
at 𝜆𝜆B1 , where 𝜀𝜀D and 𝜀𝜀M represent the absorption coefficients of D and of M,
respectively.

6pt

Solution 1:
The absorbance at the initial state is:𝜀𝜀 𝑛𝑛
𝐴𝐴B1 = D 0 𝑙𝑙𝑥𝑥
𝑉𝑉0
The absorbance after equilibrium is:𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B1 = D D
𝑙𝑙𝑥𝑥
𝑉𝑉
From the ideal gas law, the following relationship is obtained:
𝑛𝑛0
𝑃𝑃
𝑛𝑛 + 𝑛𝑛M
=
= D
(*1)
𝑉𝑉0
𝑅𝑅𝑅𝑅
𝑉𝑉
From these equations, the following relationship is obtained:
𝜀𝜀 𝑛𝑛
𝜀𝜀 (𝑛𝑛 + 𝑛𝑛M )𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B1 = D 0 𝑙𝑙𝑥𝑥 = D D
𝑙𝑙𝑥𝑥 = D D
𝑙𝑙𝑥𝑥
𝑉𝑉0
𝑉𝑉
𝑉𝑉
→ 𝜀𝜀D 𝑛𝑛M = 𝜀𝜀M 𝑛𝑛M→ 0 = (𝜀𝜀M − 𝜀𝜀D )𝑛𝑛M
As 𝑛𝑛M > 0 after the equilibrium, 𝜀𝜀D = 𝜀𝜀M holds at 𝜆𝜆B1 .
Solution 2:
Using the ideal gas law, the absorbance at the initial state is expressed as:𝑃𝑃
𝜀𝜀 𝑛𝑛
𝐴𝐴B1 = D 0 𝑙𝑙𝑥𝑥 = 𝜀𝜀D𝑙𝑙 (*2)𝑉𝑉0
𝑅𝑅𝑅𝑅 𝑥𝑥
The absorbance after equilibrium is:𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝜀𝜀 𝑝𝑝 + 𝜀𝜀M 𝑝𝑝M
𝐴𝐴B1 = D D
𝑙𝑙𝑥𝑥 = D D
𝑙𝑙𝑥𝑥 (*3)
𝑉𝑉
𝑅𝑅𝑅𝑅
From these equations, the following relationship is obtained:𝑃𝑃𝜀𝜀 𝑝𝑝 + 𝜀𝜀M 𝑝𝑝M
𝐴𝐴B1 = 𝜀𝜀D𝑙𝑙𝑥𝑥 = D D
𝑙𝑙𝑥𝑥
𝑅𝑅𝑅𝑅
𝑅𝑅𝑅𝑅
Using the fact that 𝑝𝑝D = 𝑃𝑃 𝑃𝑃𝑃M ,𝜀𝜀D 𝑃𝑃 𝑃𝑃𝑃D (𝑃𝑃 𝑃𝑃𝑃M ) + 𝜀𝜀M 𝑝𝑝M = 𝜀𝜀D 𝑃𝑃 𝑃𝑃𝑃𝑃M − 𝜀𝜀D )𝑝𝑝M
→ 0 = (𝜀𝜀M − 𝜀𝜀D )𝑝𝑝M
As 𝑝𝑝M > 0 after the equilibrium, 𝜀𝜀D /𝜀𝜀M = 1 holds at 𝜆𝜆B1 .
6 points in total:
3 points for showing conversion using ideal gas law (either eq. *1, *2, or *3).
Full marks when the correct relationship between 𝜀𝜀D and 𝜀𝜀M is shown even without any derivation
written.

Examination

125

Q3-5

IChO

English (Official)

B.2

The absorbance of the gas at 𝜆𝜆B2 measured from direction 𝑦𝑦 was 𝐴𝐴B2 both at
the initial state (𝑙𝑙 𝑙 𝑙𝑙𝑦𝑦𝑦 ) and after the equilibrium (𝑙𝑙 𝑙 𝑙𝑙𝑦𝑦 ). Determine the ratio
𝜀𝜀D /𝜀𝜀M at 𝜆𝜆B2 .

6pt

Solution 1:
The absorbance at the initial state is:𝜀𝜀 𝑛𝑛
𝐴𝐴B2 = D 0 𝑙𝑙𝑦𝑦𝑦
𝑉𝑉0
The absorbance after equilibrium is:𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B2 = D D
𝑙𝑙𝑦𝑦𝑉𝑉Using the fact that:𝑉𝑉
𝑙𝑙𝑦𝑦 = 𝑙𝑙𝑦𝑦𝑦
𝑉𝑉0
The absorbance after equilibrium is expressed as follows:
𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B2 = D D
𝑙𝑙𝑦𝑦𝑦
𝑙𝑙𝑦𝑦 = D D
𝑉𝑉𝑉𝑉0From these equations, the following relationship is obtained:
𝜀𝜀 𝑛𝑛
𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B2 = D 0 𝑙𝑙𝑦𝑦𝑦 = D D
𝑙𝑙𝑦𝑦𝑦
𝑉𝑉0
𝑉𝑉0
Using the fact that:𝑛𝑛M = 2(𝑛𝑛0 − 𝑛𝑛D ) (*4)
The following relationship is obtained:
𝜀𝜀D 𝑛𝑛0 = 𝜀𝜀D 𝑛𝑛D + 2𝜀𝜀M (𝑛𝑛0 − 𝑛𝑛D ) = 2𝜀𝜀M 𝑛𝑛0 + (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛D
→ (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛0 = (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛D
As 𝑛𝑛0 > 𝑛𝑛D after the equilibrium, 𝜀𝜀D = 2𝜀𝜀M holds at 𝜆𝜆B2 .
Solution 2:
Using the fact that 𝑉𝑉0 = 𝑙𝑙𝑦𝑦𝑦 𝑆𝑆, the absorbance at the initial state is expressed as:𝑛𝑛
𝜀𝜀 𝑛𝑛
𝐴𝐴B2 = D 0 𝑙𝑙𝑦𝑦𝑦 = 𝜀𝜀D 0
𝑉𝑉0𝑆𝑆Using the fact that 𝑉𝑉 𝑉𝑉𝑉𝑦𝑦 𝑆𝑆, the absorbance after equilibrium is expressed as:𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B2 = D D
𝑙𝑙𝑦𝑦 = D D𝑉𝑉𝑆𝑆
From these equations, the following relationship is obtained:𝑛𝑛
𝜀𝜀 𝑛𝑛 + 𝜀𝜀M 𝑛𝑛M
𝐴𝐴B2 = 𝜀𝜀D 0 = D D𝑆𝑆𝑆𝑆Using the fact that:𝑛𝑛M = 2(𝑛𝑛0 − 𝑛𝑛D ) (*4)
The following relationship is obtained:
𝜀𝜀D 𝑛𝑛0 = 𝜀𝜀D 𝑛𝑛D + 2𝜀𝜀M (𝑛𝑛0 − 𝑛𝑛D ) = 2𝜀𝜀M 𝑛𝑛0 + (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛D
→ (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛0 = (𝜀𝜀D − 2𝜀𝜀M )𝑛𝑛D
As 𝑛𝑛0 > 𝑛𝑛D after the equilibrium, 𝜀𝜀D /𝜀𝜀M = 2 holds at 𝜆𝜆B2 .
6 points in total:
3 points for showing the relationship that 𝑛𝑛M is twice of 𝑛𝑛0 − 𝑛𝑛D as in eq.*4.
Full marks when the correct relationship between 𝜀𝜀D and 𝜀𝜀M is shown even without any derivation
written.

126

The 53rd IChO 2021 Japan

Q4-1

IChO

English (Official)

The Redox Chemistry of Zinc
11 % of the total
Question

A.1

A.2

B.1

B.2

B.3

B.4

Total

Points

6

5

4

3

5

9

32

Score

Zinc has long been used as alloys for brass and steel materials. The zinc contained in industrial wastewater is separated by precipitation to detoxify the water, and the obtained precipitate is reduced to recoverand reuse it as metallic zinc.

Part AThe dissolution equilibrium of zinc hydroxide Zn(OH)2 (s) at 25 ∘ C and the relevant equilibrium constants
are given in eq. 1–4.

Examination

127

Q4-2

IChO

English (Official)

The solubility, 𝑆𝑆, of zinc (concentration of zinc in a saturated aqueous solution) is given in eq. 5.

A.1

When the equilibria in eq. 1–4 are established, calculate the pH range
in which [Zn(OH)2 (aq)] is the greatest among [Zn2+ (aq)], [Zn(OH)2 (aq)] and[Zn(OH)2−
4 (aq)].

Solution 1:
From [Zn(OH)2 (aq)] > [Zn2+ ]:𝐾𝐾sp< 𝐾𝐾1 (1')[OH− ]2
Solve this for [OH− ]:pH > 8.4[Zn(OH)2 (aq)] > [Zn(OH)2−
4 ]:
𝐾𝐾1 > 𝐾𝐾2 [OH− ]2 (2')
Solve this for [OH− ]:pH < 11.8Thus,
8.4 < pH < 11.8
Solution 2:
From (1):log[Zn2+ ][OH− ]2 = log Ksp
log[Zn2+ ] = log Ksp − 2 log [OH− ]From (2'):
log[Zn(OH)2 (aq)] = log K1[Zn(OH)2 (aq)] > [Zn2+ ]:log Ksp − 2 log [OH− ] < log K1 (1')
log Ksp − 2 (pH − 14) < log K1
From (3'):− 2log([Zn(OH)2−
4 ]/[OH ] ) = log K22−log[Zn(OH)4 ] = 2 log[OH− ] + log K2[Zn(OH)2 (aq)] > [Zn(OH)2−4 ]:log K1 > 2 log[OH− ] + log K2 (2')
log K1 > 2 (pH − 14) + log K2
Thus,
8.4 < pH < 11.8
6 points in total:
3 points for 8.4 < pH
3 points for pH < 11.8.
Partial point:
If correct answers are not obtained;(1′) and (2′): 2 points each.

128

The 53rd IChO 2021 Japan

6pt

Q4-3

IChO

English (Official)

A.2

A saturated aqueous solution of Zn(OH)2 (s) with pH = 7.00 was prepared andfiltered. NaOH was added to this filtrate to increase its pH to 12.00. Calculate
the molar percentage of zinc that precipitates when increasing the pH from 7.00
to 12.00. Ignore the volume and temperature changes.

5pt

For pH=12.00:
log[Zn(OH)2−
4 ] = −29.19 + 2 pH = −5.19
log[Zn(OH)2 (aq)] = −5.58
log[Zn2+ ] = 11.24 − 2 pH = −12.76
Thus, 𝑆𝑆 𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑆 𝑆𝑆−6 mol L−1 (1')
For pH=7.00:
log[Zn(OH)2−
4 ] = −29.19 + 2 pH = −15.19
log[Zn(OH)2 (aq)] = −5.58
log[Zn2+ ] = 11.24 − 2 pH = −2.76
Thus,
𝑆𝑆 𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑆 𝑆𝑆−3 mol L−1 (2')
The percentage of zinc precipitated is:
1.7404 × 10−3 − 9.0865 × 10−6
= 0.9948 = 99.5%
1.7404 × 10−3
5 points in total:
2 points for the correct value of (1′).
2 points for the correct value of (2′).
1 point for the final correct answer. The calculation for the negligible component is not required.

Part B
Next, the recovered zinc hydroxide is heated to obtain zinc oxide according to the reaction below:

The zinc oxide is then reduced to metallic zinc by reaction with hydrogen:

B.1

In order for reaction (7) to proceed at a hydrogen pressure kept at 1 bar, it is necessary to reduce the partial pressure of the generated water vapor. Calculate
the upper limit for the partial pressure of water vapor to allow reaction (7)to proceed at 300 ∘ C. Here, the Gibbs formation energies of zinc oxide andwater vapor at 300 ∘ C and 1 bar for all gaseous species are Δ𝐺𝐺ZnO (300∘ C) =−2.90× 102 kJ mol−1 and Δ𝐺𝐺H2 O (300∘ C) = −2.20× 102 kJ mol−1 , respectively.

4pt

Examination

129

Q4-4

IChO

English (Official)

Zn + 12 O2 → ZnO, Δ𝐺𝐺ZnO (300∘ C) = −2.90 × 102 kJ mol−1
H2 + 12 O2 → H2 O, Δ𝐺𝐺H2 O (300∘ C) = −2.20 × 102 kJ mol−1
Thus,
ZnO + H2 → Zn + H2 O, Δ𝐺𝐺 𝐺𝐺𝐺𝐺H2 O (300∘ C) − Δ𝐺𝐺ZnO (300∘ C) (1')
= 7.0 × 101 kJ mol−1
𝑝𝑝H O
Δ𝐺𝐺
ln𝐾𝐾 𝐾 ln 2 = −
(2')
𝑝𝑝H2
𝑅𝑅𝑅𝑅
From 𝑇𝑇𝑇 𝑇𝑇𝑇𝑇𝑇𝑇 K,
𝑝𝑝H2 O = 4.14 × 10−7 bar = 4.1 × 10−7 bar
4 points in total:
1 point for the correct formulation of (1′).
2 point for the correct formulation of (2′).
1 point for the correct final answer.
Metallic zinc is used as a negative electrode (anode) material for metal-air batteries. The electrode consists of Zn and ZnO. It uses the following redox reaction to generate electricity with the electromotive
force (e.m.f.) at 25 ∘ C and pressure of 1 bar, 𝐸𝐸 ∘ .

B.2

A zinc–air battery was discharged at 20 mA for 24 hours. Calculate the change
in mass of the negative electrode (anode) of the battery.

3pt

The reaction Zn → ZnO occurs at the negative electrode and consumes 2 mol electrons per mol Znoxidized.
Thus, the weight change is:0.02 × 24 × 60 × 60 × 16
𝑊𝑊 𝑊
(1')
2𝐹𝐹
= 0.14 g
3 points in total;
2 points for the correct formulation (1').
1 point for the correct final answer.

130

The 53rd IChO 2021 Japan

Q4-5

IChO

English (Official)

Mt. Fuji
B.3

Consider the change of e.m.f. of a zinc–air battery depending on the environment. Calculate the e.m.f. at the summit of Mt. Fuji, where the temperature
and altitude are −38 ∘ C (February) and 3776 m, respectively. The atmosphericpressure is represented by

5pt

at altitude ℎ [m] and temperature 𝑇𝑇 𝑇∘ C]. The molar ratio of oxygen in the atmosphere is 21%. The Gibbs energy change of reaction (8) is Δ𝐺𝐺ZnO (−38∘ C) =−3.26 × 102 kJ mol−1 at −38 ∘ C and 1 bar.

Examination

131

Q4-6

IChO

English (Official)

Solution 1:
From (9), the air pressure at 3776 m and 𝑇𝑇 𝑇 𝑇𝑇𝑇 ∘ C is
𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃𝑃 bar (1')
From the oxygen content of 21% , the partial pressure of oxygen is:
𝑃𝑃O2 =0.126 bar
From the Nernst equation (𝑇𝑇 𝑇 𝑇𝑇𝑇 ∘ C) :𝑅𝑅𝑅𝑅
1𝐸𝐸𝐸𝐸𝐸𝐸 ∘ C) − 𝐸𝐸 ∘ (−38 ∘ C) =−=−0.01048 V =−0.01 V (2')
ln
2𝐹𝐹 √𝑃𝑃O2
Δ𝐺𝐺∘ (−38 ∘ C)
326000𝐸𝐸 ∘ (−38 ∘ C) =−==1.6894 V =1.69 V (3')
2𝐹𝐹
2𝐹𝐹
From (2') and (3'):
𝐸𝐸𝐸𝐸𝐸𝐸 ∘ C) =1.68 V
Solution 2:
From (9), the air pressure at 3776 m and 𝑇𝑇 𝑇 𝑇𝑇𝑇 ∘ C is
𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃𝑃 bar (1')
From the oxygen content of 21% , the partial pressure of oxygen is:
𝑃𝑃O2 =0.126 bar
1
Δ𝐺𝐺𝐺𝐺𝐺𝐺 ∘ C) = Δ𝐺𝐺∘ (−38 ∘ C) − 𝑅𝑅𝑅𝑅 ln 𝑃𝑃O2 (2')
2=−3.24 × 102 kJ mol−1
Δ𝐺𝐺𝐺𝐺𝐺𝐺 ∘ C)
𝐸𝐸𝐸𝐸𝐸𝐸 ∘ C) =−(3')
2𝐹𝐹=1.68 V(∘ is used for 1 bar)
5 points in total:
1 point for the correct value of (1′).
2 points for the correct formulation of (2').
1 point for the correct formulation of (3')
1 point for the correct final answer.
B.4

132

Calculate the Gibbs energy change for reaction (6) at 25 ∘ C. Note that the standard reduction potentials, 𝐸𝐸 ∘ (Zn2+ /Zn) and 𝐸𝐸 ∘ (O2 /H2 O) at 25 ∘ C and 1 bar are
given as (10) and (11), respectively.

The 53rd IChO 2021 Japan

9pt

IChO

Q4-7
English (Official)

From (10):Zn2+ + 2e− → Zn, 𝐸𝐸 ∘ = −0.77 V
Δ𝐺𝐺∘ = −2𝐹𝐹 𝐹 𝐹𝐹𝐹𝐹𝐹 (1')= 148.59 kJ mol−1
From (8):Zn + 12 O2 → ZnO, 𝐸𝐸 ∘ = 1.65 V
Δ𝐺𝐺∘ = −2𝐹𝐹 𝐹 𝐹𝐹𝐹𝐹 (2')= −318.40 kJ mol−1
From (11):O2 + 4H+ + 4e− → 2H2 O, 𝐸𝐸 ∘ = 1.23 V
Δ𝐺𝐺∘ = −4𝐹𝐹 𝐹 𝐹𝐹𝐹𝐹 (3')= −474.71 kJ mol−1
From (1):Zn2+ + 2OH− → Zn(OH)2 (s), 𝐾𝐾sp = 1.74 × 10−17−1
Δ𝐺𝐺∘ = −𝑅𝑅𝑅𝑅 ln𝐾𝐾sp(4')= −95.662 kJ mol−1
From (4):H+ + OH− → H2 O, 𝐾𝐾w = 1 × 10−14
Δ𝐺𝐺∘ = −𝑅𝑅𝑅𝑅 ln𝐾𝐾w−1 (5')= −79.912 kJ mol−1
′
′
′
′
′
From (1 )×2+(2 )×2−(32 )−(4 )×2+(5 )×4
Zn(OH)2 → ZnO + H2 O, Δ𝐺𝐺∘ = 3.0 ∼ 3.4 × 103 J mol−1(distributed depending on the handling of figures)
9 points in total:
1 points for correct formulation (1′).
1 points for correct formulation (2′).
1 points for correct formulation (3′).
2 points for correct formulation (4′).
2 points for correct formulation (5′).
2 point for the correct final answer.

Examination

133

Q5-1

IChO

English (Official)

Mysterious Silicon
12 % of the total
Question

A.1

A.2

A.3

A.4

B.1

B.2

B.3

Total

Points

9

7

6

10

5

15

8

60

Score

Although silicon is also a group 14 element like carbon, their properties differ significantly.

Part A
Unlike the carbon–carbon triple bond, the silicon–silicon triple bond in a compound formulated as
R1 –Si ≡ Si–R1 (R: organic substituent) is extremely reactive. For example, it reacts with ethylene to forma cyclic product that contains a four-membered ring.

When R1 –Si ≡ Si–R1 is treated with an alkyne (R2 –C ≡ C–R2 ), the four-membered-ring compound A is
formed as an initial intermediate. Further reaction of another molecule of R2 –C ≡ C–R2 with A affords
isomers B and C, both of which have benzene-like cyclic conjugated structures, so-called ‘disilabenzenes’
that contain a six-membered ring and can be formulated as (R1 –Si)2 (R2 –C)4 .

134

The 53rd IChO 2021 Japan

Q5-2

IChO

English (Official)

The 13 C NMR analysis of the corresponding six-membered ring skeletons Si2 C4 shows two signals for B
and one signal for C.
A.1

Draw the structural formulae of A, B, and C using R1 , R2 , Si, and C, with one ofthe possible resonance structures.

9pt

Any resonance structure is acceptable.
9 points in total: 3 points for each correct answer.A: 3 points (2 points when the Si=Si–C=C fourmembered ring skeleton is drawn correctly.)B: 3 points: (2 points when the Si–Si–C–C–C–C sixmembered ring skeleton is drawn correctly. 1 point when 1,4- or 1,3-disilabenzene is depicted. 0
points when only the 1,4- or 1,3-disilabenzene is shown and R1 and R2 are drawn incorrectly.)C: 3
points: (2 points when the Si–C–C–Si–C–C six-membered ring skeleton is drawn correctly. 1 point
when 1,2- or 1,3-disilabenzene is depicted. 0 points when only the 1,2- or 1,3-disilabenzene is shown
and R1 and R2 are drawn incorrectly.)
A.2

Calculate the aromatic stabilization energy (ASE) for benzene and C (in the caseof R1 = R2 = H) as positive values, considering the enthalpy change in somehydrogenation reactions of unsaturated systems shown below (Fig. 1).

7pt

Examination

135

Q5-3

IChO

English (Official)

Fig. 1
The aromatic stabilization energy (ASE) can be calculated as the difference of the sum of the heat ofhydrogenation of each double bond and the heat of hydrogenation of the aromatic compound.
ASE for benzene: 135 × 3 − 173 = 232 kJ mol–1
ASE for 1,4-disilabenzene (C=C + 2 Si=C): (135 + 213 × 2) − 389 = 172 kJ mol–1
7 points in total: 3 points for ASE for benzene and 4 points for compound C.
3 points for the correct ASE value for benzene (2 points when the values have the correct magnitude
but are negative.).
4 points for the correct ASE value for compound C, 1,4-disilabenzene. (3 points when thevalues have the correct magnitude but are negative.) (4 points for the ASE value for 1,2disilabenzene (206 + 135 × 2) − 326 = 150 kJ mol–1 or (213 × 2 + 135) − 326 = 235 kJ mol–1 whenthe 1,2-disilabenzene is written as a structure of C. 4 points for the ASE value for 1,3disilabenzene(135 + 213 × 2) − 368 = 193 kJ mol–1 when the 1,3-disilabenzene is written as a structure of C. )When a xylene solution of C is heated, it undergoes isomerization to give an equilibrium mixture ofcompounds D and E. The molar ratio is D : E = 1 : 40.0 at 50.0 ˚C and D : E = 1 : 20.0 at 120.0 ˚C.
A.3

136

Calculate Δ𝐻𝐻 for the transformation of D to E. Assume that Δ𝐻𝐻 does not depend on temperature.

The 53rd IChO 2021 Japan

6pt

Q5-4

IChO

English (Official)1= 0.3722) : 𝐾𝐾DE = 40
𝑅𝑅𝑅𝑅
1
T = 120 ˚C = 393.15 K (= 0.3095) : 𝐾𝐾DE = 20
𝑅𝑅𝑅𝑅
Δ𝐻𝐻
Δ𝑆𝑆
According to ln 𝐾𝐾DE = –
+
𝑅𝑅𝑅𝑅
𝑅𝑅
ln 40– ln 20
ln(𝐾𝐾DE50 ) − ln(𝐾𝐾DE120 )=–= −10.5 kJ mol–1
Δ𝐻𝐻 𝐻 𝐻1
1
0.3722−0.3059−
𝑅𝑅𝑅𝑅
𝑅𝑅𝑅𝑅
T = 50 ˚C = 323.15 K (

50

120

6 points: (+4 points for the correct equation. -2 points for the positive value. )The isomerization from C to D and to E proceeds via transformations of 𝜋𝜋-bonds into 𝜎𝜎-bonds without
breaking any 𝜎𝜎-bonds. A 13 C NMR analysis revealed one signal for the Si2 C4 skeleton of D and two signals
for that of E. The skeleton of D does not contain any three-membered rings, while E has two threemembered rings that share an edge.

A.4

Draw the structural formulae of D and E using R1 , R2 , Si, and C.

10pt

Examination

137

IChO

Q5-5
English (Official)

Based on the signals observed in the 13 C NMR spectra, the following structures could be suggested
for D and E:

In addition, considering that D has no three-membered ring in its skeleton while E has two threemembered rings that share an edge, the structures of D and E can be determined to be those shown
below:

10 points in total: 5 points for each correct structure.
(4 points for incorrect substituents R1 or R2 . 3 points for other candidates based on the information from the 13 C NMR spectra; 2 points for Si-regioisomers that would satisfy the 13 C NMR spectral
information; 1 point for Si-regioisomers that would not satisfy the 13 C NMR spectral information.)
For D: 2 points for other Dewer-benzene structure (because "not contain any three-memberedrings"). For E: 2 points for other benzvalene structure (because "two three-membered rings thatshare an edge.").

Part B
Silicon is able to form highly coordinated compounds (> four substituents) with electronegative elements
such as fluorine. As metal fluorides are often used as fluorination reagents, highly coordinated silicon
fluorides also act as fluorination reagents.
The fluorination reaction of CCl4 using Na2 SiF6 was carried out as follows.
• Standardization of Na2 SiF6 solution :· Preparation
Aqueous solution F: 0.855 g of Na2 SiF6 (188.053 g mol–1 ) dissolved in water (total volume: 200 mL).
Aqueous solution G: 6.86 g of Ce2 (SO4 )3 (568.424 g mol–1 ) dissolved in water (total volume: 200 mL).
· Procedure138

The 53rd IChO 2021 Japan

Q5-6

IChO

English (Official)

Precipitation titration of a solution F (50.0 mL) by dropwise adding solution G in the presence of xylenol
orange, which coordinates to Ce3+ , as an indicator. After adding 18.8 mL of solution G, the color of thesolution changes from yellow to magenta. The generated precipitate is a binary compound that contains
Ce3+ , and the only resulting silicon compound is Si(OH)4 .
B.1

Write the balanced equation for the reaction of Na2 SiF6 with Ce2 (SO4 )3 .

5pt

Na2 SiF6 = 188.053 g mol–1 . The concentration of Na2 SiF6 in solution F is4.548 × 10–3 mol
0.855 g== 2.274 × 10–2 mol L–1 (F)200 mL
0.2 L
Ce2 (SO4 )3 = 568.424 g mol–1 . The concentration of Ce2 (SO4 )3 in solution G is
1.207 × 10–2 mol
6.860 g=
= 6.034 × 10–2 mol L–1 (G)
200 mL
0.2 L
The concentration of Ce3+ ions in G is 6.034 × 10−2 × 2 = 1.207 × 10−2 mol L−1 .
50.0
In 50.0 mL of solution F: 2.274 × 10−2 ×= 1.137 × 10−3 mol of Na2 SiF6 was included.
1000
18.8
In 18.8 mL of solution G: 6.034 × 10−2 ×= 1.134 × 10−3 mol of Ce2 (SO4 )3 was included. Ac1000
cordingly, Na2 SiF6 should react with Ce2 (SO4 )3 in a 1:1 ratio.
Ans. Na2 SiF6 + Ce2 (SO4 )3 + 4 H2 O ⟶ 2 CeF3 + Si(OH)4 + Na2 SO4 + 2 H2 SO4
5 points: (+1 points when “Na2 SiF6 + Ce2 (SO4 )3 ” is written on the left side, and +2 points when “CeF3 ”
is written on the right side of the equation; +1 points when “Si(OH)4 ” is written on the right side ofthe equation.) Full mark for showing ionic compounds, which soluble in water as ions/ion pairs suchas NaHSO4 , Na+ , H+ , and etc. (The calculation procedure is not necessary.)• Reaction of CCl4 with Na2 SiF6 :(Substance losses by e.g. evaporation are negligible during the following operations.)
Na2 SiF6 (𝑥𝑥 [g]) was added to CCl4 (500.0 g) and heated to 300˚C in a sealed pressure-resistant reaction
vessel. The unreacted Na2 SiF6 and generated NaCl were removed by filtration. The filtrate was diluted
to a total volume of 1.00 L with CCl4 (solution H). The 29 Si and 19 F NMR spectra of solution H showed SiF4
as the only silicon compound. In the 19 F NMR spectrum, in addition to SiF4 , signals corresponding to
CFCl3 , CF2 Cl2 , CF3 Cl, and CF4 were observed (cf. Table 1). The integration ratios in the 19 F NMR spectrum
are proportional to the number of fluorine nuclei.
Table 119

F NMR data

CFCl3

CF2 Cl2

CF3 Cl

CF4Integration ratio

45.0

65.0

18.0

2.0

SiF4 is hydrolyzed to form H2 SiF6 according to the following eq. 8:

Solution H (10 mL) was added to an excess amount of water, which resulted in the complete hydrolysis of
SiF4 . After separation, the H2 SiF6 generated from the hydrolysis in the aqueous solution was neutralized
and completely converted to Na2 SiF6 (aqueous solution J).
Examination

139

Q5-7

IChO

English (Official)

The precipitate of unreacted Na2 SiF6 and NaCl, which was removed by filtration in the initial step (underlined), was completely dissolved in water to give an aqueous solution (solution K; 10.0 L).
Then, additional precipitation titrations using solution G were carried out, and the endpoints of the titrations with G were as follows:·For solution J (entire amount): 61.6 mL.
·For 100 mL of solution K: 44.4 mL.
It should be noted here that the coexistence of NaCl or SiO2 has no effect on the precipitation titration.
B.2

Calculate the mass of the NaCl produced in the reaction vessel (information
underlined), and calculate the mass (𝑥𝑥 [g]) of the Na2 SiF6 used as a starting
material.

15pt

3 SiF4 + 2 H2 O ⟶ SiO2 + 2 H2 SiF6
The ratio of the consumed SiF4 and the generated H2 SiF6 should be 3:2.
As Na2 SiF6 reacts with Ce2 (SO4 )3 in a 1:1 ratio, the amount of SiF62– in the aqueous solution J is
(6.034 × 10–2 mol L−1 ) × (61.6 × 10−3 L) = 3.717 × 10–3 mol. Considering the equation shown above,3
10 mL of the diluted solution H contains 3.717 × 10–3 mol × = 5.576 × 10−3 mol of SiF4 . Thus, 1.00
21000
L of diluted solution H contains 5.576 × 10–3 mol ×= 5.576 × 10−1 mol of SiF4 .
10
The amount of fluorine atoms that replace the chlorine atoms of CCl4 should be twice the amountof SiF4 formed during the reaction. Thus, 2 × 0.5576 = 1.115 mol of F– should replace Cl– to result in
the formation of NaCl. 1.115 mol × 58.44 g mol–1 = 65.17 g of NaCl was formed.
Ans.: 65.2 g (NaCl)
As Na2 SiF6 reacts with Ce2 (SO4 )3 in a 1:1 ratio, the amount of SiF62− in 100 mL of aqueous solution
K is 44.4 × 10−3 L × (6.034 × 10−2 mol L−1 ) = 2.679 × 10−3 mol. Accordingly, the residual amount10.0 Lof Na2 SiF6 in 10.0 L of aqueous solution K is 2.679 × 10−3 mol ×= 0.2679 mol. In total, the
100 mLamount of Na2 SiF6 used as a starting material is (0.2679 mol + 0.5576 mol) × 188.0 g mol–1 = 155.2 g
Ans.: 155 g (Na2 SiF6 )15 points in total:·10 points for the correct amount of NaCl:+3 points for the amount of SiF62– in solution J (3.717 × 10–3 mol)
+2 point for the amount of SiF4 in 10 mL of the diluted solution H (5.576 × 10−3 mol)
+2 point for the amount of SiF4 in 1.00 L of the solution H (5.576 × 10−1 mol)
+2 points for the amount of NaCl in mol (1.115mol)+1 point when the amount of NaCl is shown in gram.
·5 points for the correct amount of Na2 SiF6 :+2 points for the amount of SiF62– in solution K (2.68 × 10–3 mol)
+1 point for the amount of SiF62– before dilution to prepare solution K (2.68 × 10–1 mol)
+1 point for the addition of the amount of SiF4 in solution H (8.26 × 10–1 mol)
+1 for answering the initial amount of Na2 SiF6 in [g].
B.3

140

77.8% of the CCl4 used as a starting material was unreacted. Calculate the massof CF3 Cl generated.

The 53rd IChO 2021 Japan

8pt

IChO

Q5-8
English (Official)

500.0 g = 3.250 mol of CCl4 was initially used as a starting material. Thus, the amount of the productsthat contain at least one F atom is 3.250 mol × 0.222 = 0.721 mol.
The ratio of integrals in the 19 F NMR spectrum is CFCl3 ∶ CF2 Cl2 ∶ CF3 Cl ∶ CF4 = 45.0 : 65.0 : 18.0
: 2.0. Thus, the mole ratio of these compounds should be CFCl3 ∶ CF2 Cl2 ∶ CF3 Cl ∶ CF4 = 45.0
: 32.5 : 6.0 : 0.5 = 90 : 65 : 12 : 1. Accordingly, the amount of CF3 Cl (104.46 g mol–1 ) is
12
0.721 mol ×= 0.0515 mol = 0.0515 × 104.46 g = 5.38 g
90 + 65 + 12 + 1
Ans.: 5.38 g
8 points: (6 points for the answer in [mol]; 4 points for the correct molar ratio of substances
CFCl3 ∶ CF2 Cl2 ∶ CF3 Cl ∶ CF4 = 90 : 65 : 12 : 1).

Examination

141

Q6-1

IChO

English (Official)

The Solid-State Chemistry of Transition Metals
13 % of the total
Question

A.1

A.2

A.3

B.1

B.2

B.3

B.4

C.1

C.2

C.3

Total

Points

6

3

3

6

4

4

4

5

5

5

45

Score

Volcano at Sakurajima island

Part A
Japan is one of the countries with the highest numbers of volcanos worldwide. When silicate minerals
crystallize from magma, a part of the transition-metal ions (Mn+ ) in the magma is incorporated into thesilicate minerals. The Mn+ studied in the problem are coordinated by oxide ions (O2− ) and adopt a fourcoordinate tetrahedral (𝑇𝑇d ) geometry in the magma and six-coordinate octahedral (𝑂𝑂h ) geometry in thesilicate minerals, both of which exhibit a high-spin electron configuration. The distribution coefficient of
Mn+ between the silicate minerals and magma, 𝐷𝐷, can be expressed by:where [M]s and [M]l are the concentrations of Mn+ in the silicate minerals and the magma, respectively.
The table below shows the 𝐷𝐷 values of Cr2+ and Mn2+ as examples.

142

The 53rd IChO 2021 Japan

IChO

Q6-2
English (Official)

Let ΔO and CFSEO be the energy separation of the d-orbitals of Mn+ and the crystal-field stabilizationenergy in a 𝑂𝑂h field, respectively. Let ΔT and CFSET be those in a 𝑇𝑇d field.
A.1

Calculate |CFSEO −CFSET | = ΔCFSE in terms of ΔO for Cr2+ , Mn2+ , and Co2+ ;assume ΔT = 4/9ΔO .

6pt

The d-orbitals of a six-coordinate octahedral complex split into two groups eg (d𝑥𝑥2 −𝑦𝑦2 , d𝑧𝑧2 ), and t2g(d𝑥𝑥𝑥𝑥 , d𝑦𝑦𝑦𝑦 , d𝑧𝑧𝑧𝑧 ) with an energy separation of ΔO . The energies of the eg and t2g orbitals relative to thebarycenter are +0.60ΔO and –0.40ΔO , respectively. Likewise, the d-orbitals of a four-coordinate tetrahedral complex split into two groups t2 (d𝑥𝑥𝑥𝑥 , d𝑦𝑦𝑦𝑦 , d𝑧𝑧𝑧𝑧 ) and e (d𝑥𝑥2 −𝑦𝑦2 , d𝑧𝑧2 ) with an energy separationof ΔT . The energies of the t2 and e orbitals relative to the barycenter are +0.40ΔT and –0.60ΔT , respectively. Therefore, in the case of a high-spin electron configuration, CFSEO and CFSET for Cr2+
(3d4 ∶ t2g 3 eg 1 or e2 t2 2 ) are –0.60ΔO and –0.40ΔT (= –0.18ΔO ), respectively. CFSEO and CFSET for Mn2+
(3d5 ∶ t2g 3 eg 2 or e2 t2 3 ) are both zero. CFSEO and CFSET for Co2+ (3d7 ∶ t2g 4 eg 3 or e4 t2 3 ) are –0.80ΔO
and –1.2ΔT (= –0.53ΔO ), respectively. Accordingly, |CFSEO −CFSET | = ΔCFSE values for each metal ion
are,
Cr2+ : |–0.60ΔO – (–0.18ΔO )| = 0.42ΔO , Mn2+ : 0, Co2+ : |–0.80ΔO – (–0.53ΔO )| = 0.27ΔO
6 points in total: 2 points each for ΔCFSE of the three divalent metal ions.
A.2

A linear relationship is observed by plotting ln𝐷𝐷 against ΔCFSE / ΔO in the Cartesian coordinate system shown below.
Estimate 𝐷𝐷 for Co2+ .

3pt

Examination

143

IChO

Q6-3
English (Official)

The coordinates of Mn2+ and Cr2+ are (0, 0.095) and (0.42, 1.97), respectively. The linear regression
line calculated from these coordinates would be
y = 4.46x + 0.100
ΔCFSE of Co2+ is 0.27ΔO
Therefore, 𝐷𝐷 = exp(4.46 × 0.27 + 0.100) = 3.68 (= 3.7)
Whether the graph is drawn does not affect grading.
If the coordinates of Mn2+ and Cr2+ are correctly plotted and the 𝐷𝐷 is estimated with guide of thegraph, full mark is given.

3 points for the calculation of 𝐷𝐷.
Partial credit of 2 points if the ln𝐷𝐷 is correctly estimated from the linear regression line or the graph.
If the intercept of the linear regression line is assumed as zero (i.e., Mn2+ is at the origin of thecoordinate), full mark is given.
In order to avoid double punishment with A.1: If the answers of A.1 were wrong but the coordinatesof Mn2+ and Cr2+ are correctly plotted in the graph (or simultaneous equations are given) according
to the answers of A.1, and 𝐷𝐷 of Co2+ is correctly estimated from ln𝐷𝐷 assuming a linear relationship,
full mark is given.
Metal oxides MO (M: Ca, Ti, V, Mn, or Co) crystallize in a rock-salt structure wherein the Mn+ adopts an 𝑂𝑂hgeometry with a high-spin electron configuration. The lattice enthalpy of these oxides is mainly governedby the Coulomb interactions based on the radius and charge of the ions and some contributions fromthe CFSE of Mn+ in the 𝑂𝑂h field.

144

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IChO

Q6-4
English (Official)

A.3

Choose the appropriate set of lattice enthalpies [kJ mol−1 ] from one of the options (a) to (f).

3pt

The lattice enthalpy is determined by the Coulomb interactions, which are proportional to the product of the valences of the constituent ions and inversely proportional to the sum of the ionic radii.
As the target compounds are oxides of divalent metal ions, we should consider the ionic radii of themetal ions. The radii of divalent metal ions within the same period decrease with increasing atomic
number. Let us compare the lattice enthalpies of CaO and MnO with no contribution from the CFSE:
The ionic radius of Mn2+ is smaller than that of Ca2+ , and therefore, the lattice enthalpy is higher for
MnO. So, the participants should choose (a), (b), or (c). Then, let us compare the lattice enthalpies ofTiO (d2 ) and VO (d3 ): The ionic radius of V2+ is smaller than that of Ti2+ , and the CFSE is higher for VO
than for TiO. Accordingly, the lattice enthalpy is also higher for VO. Based on these observations, theanswer should be (a) or (c). Finally, let us compare the lattice enthalpies of TiO (d2 ) and CoO (d7 ): Theionic radius of Co2+ is smaller than that of Ti2+ , while their CFSEs are equal. Thus, the lattice enthalpy
is higher for CoO. Thus, the correct answer is (a). Partial credit is given for (b) and (c).
3 points for the correct answer (a). Partial credit of 2 points for (c) and 1 point for (b).

Part B
A mixed oxide A, which contains La3+ and Cu2+ , crystallizes in a tetragonal unit cell shown in Fig.1. In the[CuO6 ] octahedron, the Cu–O length along the z-axis (𝑙𝑙𝑧𝑧 ) is longer than that of the x-axis (𝑙𝑙𝑥𝑥 ), and [CuO6 ]is distorted from the regular 𝑂𝑂h geometry. This distortion removes the degeneracy of the eg orbitals(d𝑥𝑥2 −𝑦𝑦2 and d𝑧𝑧2 ).

Examination

145

Q6-5

IChO

English (Official)

Fig. 1
A can be synthesized by thermal decomposition (pyrolysis) of complex B, which is formed by mixing metal
chlorides in dilute aqueous ammonia solution containing squaric acid C4 H2 O4 , i.e., a diacid. The pyrolysis
behavior of B in dry air shows a weight loss of 29.1% up to 200 °C due to the loss of crystallization water,
followed by another weight loss up to 700 °C due to the release of CO2 . The total weight loss during theformation of A from B is 63.6%. It should be noted that only water and CO2 are released in the pyrolysis
reaction.
B.1

Write the chemical formulae for A and B.

6pt

The unit cell shown in Fig. 1 contains four La3+ , two Cu2+ , and eight O2− ions. Therefore, A: La2 CuO4 .
As the formula weight of La2 CuO4 is 405.3, that of B should be 1113.5 considering the following
equation: 405.3 ÷ (1 – 0.636). Given that the weight loss due to crystallization water is 29.1%, thenumber of molecules of crystallization water is 18.00 considering the following equation: (1113.5
× 0.291) ÷ 18 (18H2 O; M = 324). Complex B is a trinuclear complex that consists of two La3+ and
one Cu2+ ions. Considering that the synthetic solution is basic, the squaric acid is deprotonated and2−
coordinates to the metal ion as C4 O4 . The number of squaric acid molecules is 4.00 based on the2−
following equation: (1113.5 – 138.9 × 2 – 63.5 – 324) ÷ 112 (C4 O4 ; M = 112). B: La2 Cu(C4 O4 )4 (H2 O)18
(La2 CuC16 O34 H36 )6 points in total (2 and 4 points for A and B, respectively). Partial credit of 2 points for the correct
number of crystallization water (La2 Cu(H2 O)18 ) for B. (full marks are also given for A: La4 Cu2 O8 and
B: La4 Cu2 (C4 O4 )8 (H2 O)36 (La4 Cu2 C32 O68 H72 ), which correspond to the numbers of elements in theunit cell)
B.2

146

Calculate 𝑙𝑙𝑥𝑥 and 𝑙𝑙𝑧𝑧 using Fig. 1.

The 53rd IChO 2021 Japan

4pt

Q6-6

IChO

English (Official)

𝑙𝑙𝑥𝑥 : 0.3833 ÷ 2 = 0.1917 (= 0.192 nm).
𝑙𝑙𝑧𝑧 : (1.3313 – 0.2520 × 2) ÷ 4 = 0.2068 (= 0.207 nm)
4 points in total (2 points for each correct answer).
B.3

For Cu2+ in the distorted [CuO6 ] octahedron in A of Fig. 1, write the names of the
split eg orbitals (d𝑥𝑥2 −𝑦𝑦2 and d𝑧𝑧2 ) in (i) and (ii), and draw the electron configurationin the dotted box in your answer sheet.

4pt(i) d𝑥𝑥2 −𝑦𝑦2 , (ii) d𝑧𝑧2

4 points in total: 2 points for the correct names of the orbitals in (i) and (ii), and 2 points for the correct
electron configuration in the dotted box. Full mark is given even spin up and down directions of theelectrons are not shown (the electrons can be shown in arrows, lines, circles etc.).
A is an insulator. When one La3+ is substituted with one Sr2+ , one hole is generated in the crystal latticethat can conduct electricity. As a result, the Sr2+ -doped A shows superconductivity below 38 K. When asubstitution reaction took place for A, 2.05 × 1027 holes m−3 were generated.
B.4

Calculate the percentage of Sr2+ substituted for La3+ based on the mole ratio
in the substitution reaction. Note that the valences of the constituent ions andthe crystal structure are not altered by the substitution reaction.

4pt

The corresponding reaction equation, where the amount of Sr2+ is x%, is:
La2 CuO4 + (2x/100)Sr2+ → [La2(1−x/100) Sr(2x/100) CuO4 ](2x/100)− + (2x/100)La3+
The charge of [La2(1−x/100) Sr(2x/100) CuO4 ] is negative, and the amount of doped holes is (2x/100)h+
per mole. The volume of the unit cell is 0.38332 × 1.3313 = 0.1956 nm3 . The unit cell contains four
La3+ , two Cu2+ , and eight O2− ions, i.e., the unit contains two La2 CuO4 . Accordingly, the number ofholes per unit cell is (4x/100).
Since the concentration of holes is the number of holes divided by the unit cell volume, the following
equation is satisfied: (4x/100)/(0.1956 × 10−27 ) = 2.05 × 10−27 , x = 10%
Alternative answer without giving the substitution reaction; density of La3+ in the unit cell4/(0.38332 × 1.3313) = 20.45 nm−3
Density of holes in the unit cell is 2.05 nm−3
Therefore, the percentage of substitution is 2.05/20.45 × 100 = 10%
4 points for the correct answer; whether the substitution reaction is given does not affect grading;partial credit of 1 point for 20% (forgetting that the unit cell contains two La2 CuO4 ).
Examination

147

Q6-7

IChO

English (Official)Part C−2+

Cu2 (CH3 CO2 )4 is composed of four CH3 CO2 coordinated to two Cu (Fig. 2A). Cu2 (CH3 CO2 )4 exhibits−high levels of structural symmetry, with two axes passing through the carbon atoms of the four CH3 CO2
2+
and an axis passing through the two Cu , all of which are oriented orthogonal relative to each other.
−
When a dicarboxylate ligand is used instead of CH3 CO2 , a “cage complex” is formed. The cage com2+
L1
L1)4 is composed of planar dicarboxylate L1 (Fig. 2B) and Cu (Fig. 2C). The angle θ between
plex Cu4 (L1the coordination directions of the two carboxylates, indicated by the arrows in Fig. 2B, determines the
structure of the cage complex. The θ is 0° for L1. Note that hydrogen atoms are not shown in Fig. 2.

Fig. 2
C.1

148

The θ of the planar dicarboxylate L2 below is fixed to 90˚. If the composition
2+
L2L2)𝑚𝑚 , give the smallestof the cage complex formed from L2 and Cu is Cu𝑛𝑛 (L2−integer combination of n and m. Assume that only the CO2 groups of L2 form2+
a coordination bond to Cu ions.

The 53rd IChO 2021 Japan

5pt

Q6-8

IChO

English (Official)n = m = 12

5 points in total. Partial credit of 2 points for all answers with n : m = 1 : 1 (charge neutrality is2+2+satisfied but Cu would not be 4-coordinate) or n = 6, m = 12 (Cu is 4-coordinate but the complex
would be an anion).
2+−

A zinc complex, Zn4 O(CH3 CO2 )6 , contains four tetrahedral Zn , six CH3 CO2 , and one O2− (Fig. 3A). In
Zn4 O(CH3 CO2 )6 , the O2− is located at the origin, and the three axes passing through the carbon atoms of−
CH3 CO2 are oriented orthogonal relative to each other. When p-benzenedicarboxylate (Fig. 3B, L3, θ =−2+180°) is used instead of CH3 CO2 , the Zn clusters are linked to each other to form a crystalline solid (X)L3L3)3 ]𝑛𝑛 , and it hasthat is called a “porous coordination polymer” (Fig. 3C). The composition of X is [Zn4 O(L3a cubic crystal structure with nano-sized pores. One pore is represented as a sphere in Fig. 3D, and each2+
tetrahedral Zn cluster is represented as a dark gray polyhedron in Fig. 3C and 3D. Note that hydrogenatoms are not shown in Fig. 3.

Examination

149

Q6-9

IChO

English (Official)

Fig. 3
C.2

X has a cubic unit cell with a side length of 𝑎𝑎 (Fig. 3C) and a density of 0.592
g cm−3 . Calculate 𝑎𝑎 in [cm].

5pt

L3
The molecular weight of Zn4 O(L3L3)3 is 770.
L3L3)3 units in the unit cell. Therefore, the molecular
According to Figure 3C, there are eight Zn4 O(L3weight per unit cell can be calculated as 770 × 8 = 6160.
The weight of the unit cell is 6160 ÷ 𝑁𝑁A = 1.02 × 10−20 g
Let the length of the side of the unit cell be 𝑎𝑎 [cm], then, (1.02 × 10−20 ) g / 𝑎𝑎3 [cm3 ] = 0.592 g cm−3 .
𝑎𝑎 = 2.6 × 10−7 cm
5 points in total.
Partial credit of 3 points for the correct formulation to derive the molecular weight of the unit cell; 2points for the correct value of 𝑎𝑎.

C.3

150

X contains a considerable number of pores, and 1 g of X can accommodate
3.0 × 102 mL of CO2 gas in the pores at 1 bar and 25 °C. Calculate the average
number of CO2 molecules per pore.

The 53rd IChO 2021 Japan

5pt

IChO

Q6-10
English (Official)

L3
There is one pore per Zn4 O(L3L3)3 unit.
Number of pores [mol] per 1 [g] of X: 1 [g] / 770 = 0.00130.
Based on the ideal gas equation, 3.0 × 102 [mL] of adsorbed CO2 corresponds to:(1 × 105 [Pa] × 3.0 × 10−4 [m3 ]) / (8.31 × 298 [K]) = 0.0121 [mol] of CO2 .
Therefore, 0.0121 ÷ 0.00130 = 9.3 molecules of CO2 per pore.
5 points in total.
Partial credit of 3 points for the correct formulation to calculate the number of pores in 1 g; 2 points
for the correct calculation of the number of molecules of CO2 per pore.

Examination

151

Q7-1

IChO

English (Official)

Playing with Non-benzenoid Aromaticity
13 % of the total
Question

A.1

A.2

A.3

B.1

Total

Points

5

2

19

10

36

Score

Prof. Nozoe (1902–1996) opened the research field of non-benzenoid aromatic compounds, which are
now ubiquitous in organic chemistry.

Photo courtesy: Tohoku Univ.

Part A
Lineariifolianone is a natural product with a unique structure, which was isolated from Inula linariifolia.
From valencene (1), a one-step conversion yields 2, before a three-step conversion via 3 yields ketone 4.
Eremophilene (5) is converted into 6 by performing the same four-step conversion.

152

The 53rd IChO 2021 Japan

Q7-2

IChO

English (Official)

Inula linariifolia

A.1

Draw the structures of 2 and 6 and clearly identify the stereochemistry where
necessary.

5pt

Examination

153

IChO

Q7-3
English (Official)

2 (2 pt in total):–1 pt for missing double bond,–1 pt for stereochemistry error.
6 (3 pt in total):–1 pt for missing double bond,–2 pt for stereochemistry error.
Then, ketone 4 is converted into ester 15. Compound 8 (molecular weight: 188) retains all the stereocenters in 7. Compounds 9 and 10 have five stereocenters and no carbon-carbon double bonds. Assume
that H2 18 O is used instead of H2 16 O for the synthesis of 18 O-labelled-lineariifolianones 13 and 14 from 11
and 12, respectively. Compounds 13 and 14 are 18 O-labelled isotopomers. Ignoring isotopic labelling,both 13 and 14 provide the same product 15 with identical stereochemistry.

154

The 53rd IChO 2021 Japan

IChO

Q7-4
English (Official)

Examination

155

Q7-5

IChO

English (Official)

A.2

Choose the appropriate structure for A.

2pt

III
A is reacted with the potassium enolate of 4, thus I, II, IV are inappropriate because these reagents
have acidic protons.
2 pt in total
others: 0 pt
A.3

156

Draw the structures of 8–14 and clearly identify the stereochemistry where necessary. Also, indicate the introduced 18 O atoms for 13 and 14 as shown in theexample below.

The 53rd IChO 2021 Japan

19pt

IChO

Q7-6
English (Official)

Examination

157

IChO

Q7-7
English (Official)

8 (3 pt in total):–1 pt each for missing one double bond or drawing an allene instead of an alkyne,
0 pt for incorrect planar structure,-2 pt for an opposite stereochemistry next to the alkyne,-2 pt for other stereochemistry errors.
9–12 (2 pt each, 8 pt in total):–1 pt each for missing atoms (e.g., fluorine atom, oxygen of epoxide),-1 pt for stereochemistry error,
Two sets of compounds 9, 11, 13 and 10, 12, 14 are interconvertible,
Structures of 13 and 14/18 O labelling on hydroxy groups of 13 and 14 (3 pt each, 6 pt in total):-1 pt each for incorrect or unclear 18 O labelling on the diol moiety,-1 pt each for incomplete transformation (diol only, ketone only),
0 pt for incorrect planar structure other than the above,-2 pt for stereochemistry error.
18
O labelling on carbonyl group of 13 and 14 (1 pt each, 2 pt in total):
0 pt when 18 O is incorporated in the carbonyl group of neither 13 nor 14.

158

The 53rd IChO 2021 Japan

IChO

Q7-8
English (Official)Part B
Compound 19 is synthesized as shown below. In relation to non-benzenoid aromaticity, 19 can be used
as an activator for alcohols, and 20 was converted to 22 via ion-pair intermediate 21. Although theformation of 21 was observed by NMR, 21 gradually decomposes to give 18 and 22.

B.1

Draw the structures of 17–19 and 21. Identifying the stereochemistry is notnecessary.

10pt

Examination

159

IChO

Q7-9
English (Official)

17 (2 pt in total):
stereochemistry is ignored,
0 pt for bromination on aryl ring.
18 (2 pt in total):
19 (3 pt in total):
Full mark for ionic structure.
21 (3 pt in total):–1 pt when Cl− is omitted,–1 pt when C–Cl is covalent,–1 pt each for other errors on connectivity,–1 pt when the alkoxide and chlorocyclopropenium are given.

160

The 53rd IChO 2021 Japan

Q8-1

IChO

English (Official)

Dynamic Organic Molecules and Their Chirality
11 % of the total
Question

A.1

A.2

A.3

B.1

B.2

Total

Points

9

3

7

3

4

26

Score

Part A
Polycyclic aromatic hydrocarbons with successive ortho-connections are called [n]carbohelicenes (here,n represents the number of six-membered rings) (see below). [4]Carbohelicene ([4]C) is efficiently prepared by a route using a photoreaction as shown below, via an intermediate (Int.) that is readily oxidized
by iodine.

The photoreaction proceeds in a manner similar to the following example.

Examination

161

Q8-2

IChO

English (Official)

Note: For all of Question 8, please draw alternating single and double bonds in your answers to
the problems as depicted in the examples of carbohelicene. Do not use circles for conjugated 𝜋𝜋systems.
A.1

Draw the structures of A–C. Stereoisomers should be distinguished.

9pt

3 points each. When B and C are reversed, give 1 point each. When missing double bonds in B andC, -1 point each.
If B is blank and C is the trans-isomer (i.e. B), give 2 points for C.
-1 point for each "circled" answer (this is applied for all the following questions in Q8)
A.2

162

Attempts to synthesize [5]carbohelicene from the same phosphonium salt andan appropriate starting compound resulted in the formation of only a trace
amount of [5]carbohelicene, instead affording product D whose molecularweight was 2 Da lower than that of [5]carbohelicene. The 1 H NMR chemical
shifts of D are listed below. Draw the structure of D.
[D (𝛿𝛿, ppm in CS2 , r.t.), 8.85 (2H), 8.23 (2H), 8.07 (2H), 8.01 (2H), 7.97 (2H), 7.91
(2H)]

The 53rd IChO 2021 Japan

3pt

IChO

Q8-3
English (Official)

Structural isomer D’: 1 point
Structural isomer D’’: 1 point
Any careless mistakes such as contamination with sp3 carbons: -1 point each.

Examination

163

Q8-4

IChO

English (Official)[5]- and larger [n]carbohelicenes have helical chirality and interconversion between enantiomers of thesehelicenes is significantly slow at room temperature. The chirality of [n]carbohelicenes is defined as (M)or (P) as shown below.

[n]Carbohelicenes with n larger than 4 can be enantiomerically separated by a chiral column chromatography, which was developed by Prof. Yoshio Okamoto.

Photo courtesy: The Japan Prize Foundation
Multiple helicenes are molecules that contain two or more helicene-like structures. If its helical chirality
is considered, several stereoisomers exist in a multiple helicene. For example, compound E contains
three [5]carbohelicene-like moieties in one molecule. One of the stereoisomers is described as (P, P, P)
as shown below.

164

The 53rd IChO 2021 Japan

IChO

Q8-5
English (Official)

A.3

The nickel-mediated trimerization of 1,2-dibromobenzene generates triphenylene. When the same reaction is applied to an enantiomer of F, (P)-F, multiple
helicene G (C66 H36 ) is obtained. Given that interconversion between stereoisomers does not occur during the reaction, identify all the possible stereoisomers of G formed in this process, without duplication. As a reference, one isomer should be drawn completely with the chirality defined as in the example
above, with numerical labels; the other stereoisomers should be listed with location numbers and M and P labels according to the same numbering. For instance, the other stereoisomers of E should be listed as (1, 2, 3) = (P, M, P), (P,M, M), (P, P, M), (M, M, M), (M, M, P), (M, P, P), and (M, P, M).

7pt

Examination

165

Q8-6

IChO

English (Official)

A representative example

One structure should be drawn fully; chemical structure (2 points) and its stereochemistry (1 point
for the original chirality (outside), 1 point for the new chirality (inside))
For the other three isomers (1 point each).
Overcount (answering the same stereochemistry multiple times for an isomer) (-1 point each; thisreduction is applied repeatedly up to 4 times).
0 points if no representative structure is drawn.

166

The 53rd IChO 2021 Japan

IChO

Q8-7
English (Official)Part B
Sumanene is a bowl-shaped hydrocarbon that was first reported in Japan in 2003. The name "sumanene"derives from a Sanskrit-Hindi word "suman" that means sunflower. The synthesis of sumanene wasachieved by a reaction sequence that consists of a ring-opening and a ring-closing metathesis.

Representative metathesis reactions catalyzed by a ruthenium catalyst (Ru*) are shown below.

B.1

Draw the structure of intermediate I (its stereochemistry is not required).

3pt

Examination

167

IChO

Q8-8
English (Official)

Double bond saturation (such as I’): 0 points.
Any careless mistakes such as contamination with wrong sp2 carbon atoms: -1 point each.
Any different carbon frameworks: 0 points.

168

The 53rd IChO 2021 Japan

Q8-9

IChO

English (Official)

B.2

Starting from the optically active precursor J, the same reaction sequence gives
the optically active sumanene derivative K. The stereocenters in J suffer no inversion during the metathesis reaction. Draw the structure of K with the appropriate stereochemistry.

4pt

No stereochemistry: 1 point.
The other enantiomer: 2 points.
Lower-symmetry structure (Me at a different position): 0 points.

Examination

169

Q9-1

IChO

English (Official)

Likes and Dislikes of Capsule
10 % of the total
Question

A.1

A.2

A.3

A.4

A.5

Total

Points

13

2

2

3

3

23

Score

Good kids don’t do this, but if you unseam a tennis ball, you can disassemble it into two U-shaped pieces.

Based on this idea, compounds 1 and 2 were synthesized as U-shaped molecules with different sizes.
Compound 3 was prepared as a comparison of 1 and the encapsulation behavior of these compounds
was investigated.

170

The 53rd IChO 2021 Japan

IChO

Q9-2
English (Official)

The synthetic route to 2 is shown below. The elemental composition of compound 9: C; 40.49%, H; 1.70%,
and O; 17.98% by mass.

Examination

171

Q9-3

IChO

English (Official)

A.1

172

Draw the structures of 4–9; the stereochemistry can be neglected. Use "PMB"
as a substituent instead of drawing the whole structure of p-methoxybenzyl
group shown in the scheme above.

The 53rd IChO 2021 Japan

13pt

Q9-4

IChO

English (Official)

4 (2 pt)

5 (3 pt)

6 (2 pt)

7 (2 pt)

8 (2 pt)

9 (2 pt)·2 points for the correct structures of compounds 4 and 6-9.
·3 points for the correct structure of compound 5.
·For compounds 4-9, any careless mistakes such as the wrong number of carbons or forgetting towrite double or triple bonds: -1 point each.
·For compound 6, 1 point for structures that show the reduced double bond in a different position.
·Full mark will be given if a structure of p-methoxybenzyl group is drawn instead of using PMB.
· minimum score: 0 points.
In the mass spectrum of 1, the ion peak corresponding to its dimer (112 ) was clearly observed, whereas
Examination

173

Q9-5

IChO

English (Official)

an ion peak for 3 2 was not observed in the spectrum of 3. In the 1 H NMR spectra of a solution of 1 2 ,all the NH protons derived from 1 were observed to be chemically equivalent, and their chemical shift
was significantly different from that of the NH protons of 3. These data indicate that hydrogen bonds
are formed between the NH moieties of 1 and atoms X of another molecule of 1 to form the dimericcapsule.
A.2

Circle all the appropriate atom(s) X in 1.

2pt

2 points for the correct answer
A.3

Give the number of the hydrogen bonds in the dimeric capsule (112 ).

2pt

8 (because 8 NH protons were observed equally in the 1 H NMR spectrum of the dimer.)2 points for the correct answer.
The dimeric capsule of 1 (112 ) has an internal space wherein an appropriate small molecule Z can be
encapsulated. This phenomenon is expressed by the following equation:

The equilibrium constant of the encapsulation of Z into 1 2 is given as below:

Encapsulation of a molecule into a capsule could be monitored by NMR spectroscopy. For example, 1 2
in C6 D6 gave different signals in the 1 H NMR spectra before and after addition of CH4 .
Compound 2 also forms a rigid and larger dimeric capsule (222 ). The 1 H NMR spectrum of 2 2 was measured
in C6 D6 , C6 D5 F, and a C6 D6 /C6 D5 F solvent mixture, with all other conditions being kept constant. The
chemical shifts for the Ha proton of 2 in the above solvents are summarized below, and no other signals
from the Ha in 2, except for the listed, were observed. Assume that the interior of the capsule is always
filled with the largest possible number of solvent molecules and that each signal corresponds to one
species of the filled capsule.
174

The 53rd IChO 2021 Japan

Q9-6

IChO

English (Official)

A.4

solvent𝛿𝛿 (ppm) of Ha

C6 D6

4.60

C6 D5 F

4.71

C6 D6 / C6 D5 F

4.60, 4.71, 4.82

Determine the number of C6 D6 and C6 D5 F molecules encapsulated in 2 2 giving
each Ha signal.

3pt

1 point for the correct number of encapsulated C6 D6 and C6 D5 F molecules for each NMR signal.
𝛿𝛿 (ppm) of Ha

numbers of C6 D6numbers of C6 D5 F

4.60 ppm

204.71 ppm

024.82 ppm

1

1

The observation of the third signal in the mixed solvent indicates that two solvent molecules are
initially encapsulated in the capsule. Thus, the signal at 4.82 ppm is ascribed to a capsule containing
one molecule of C6 D6 and one molecule of C6 D5 F.
H NMR measurements in C6 D6 revealed that 2 2 can incorporate one molecule of 1-adamantanecarboxylic
acid (AdA), and the association constants (𝐾𝐾a ) which are expressed below were determined for various
temperatures. [solvent@222 ] denotes a species containing one or more solvent molecules.

1

Similarly, the 𝐾𝐾a values of CH4 and 1 2 given as eq (2) at various temperatures in C6 D6 were also determined by 1 H NMR measurements. The plots of the two association constants (as ln 𝐾𝐾a vs 1/T) are shown
below.

Examination

175

Q9-7

IChO

English (Official)

No C6 D6 molecule is encapsulated in 1 2 . In line II, the entropy change (Δ𝑆𝑆) is ( 1 ) and enthalpy change(Δ𝐻𝐻) is ( 2 ), indicating that the driving force for the encapsulation in line II is ( 3 ). Therefore, line I
corresponds to ( 4 ), and line II corresponds to ( 5 ).
A.5

Choose the correct options in gaps (1)–(5) in the following paragraph from A
and B.
AB(1)

positive

negative(2)

positive

negative

(3)

Δ𝑆𝑆

Δ𝐻𝐻

(4)

1 2 and CH4

2 2 and AdA(5)

1 2 and CH4

2 2 and AdA

3pt(1): A(2): A(3): A(4): A(5): B
3 points in total
2 points for correct answers for (1)-(3).
1 point for correct answers for (4) and (5).
No points when the former part ((1)-(3)) is incorrect even if the latter part ((4) and (5)) is correct.
Transforming Δ𝐺𝐺 𝐺 𝐺𝐺𝐺𝐺𝐺 ln 𝐾𝐾𝑎𝑎 = Δ𝐻𝐻 𝐻𝐻𝐻𝐻𝐻𝐻 gives
Δ𝐻𝐻
Δ𝑆𝑆
ln 𝐾𝐾𝑎𝑎 =−
+
𝑅𝑅𝑅𝑅
𝑅𝑅
(If Δ𝐻𝐻 is negative, the slope is positive; if the y-intercept is negative, Δ𝑆𝑆 is negative.)
The relationship between 1 2 and CH4 is that the entropy change is unfavorable (Δ𝑆𝑆 < 0) given thatthe two components become one component. Nevertheless, the encapsulation of CH4 occurs (Δ𝐺𝐺 <0), indicating that the enthalpy change is exothermic and favorable (Δ𝐻𝐻 < 0). This result indicates aplot with a positive slope and a negative y-intercept for 1 2 and CH4 .
Therefore, the plot with a negative slope (Δ𝐻𝐻 > 0) and positive y-intercept (Δ𝑆𝑆 > 0) is 22 and AdA.
This is due to the release of the two molecules of C6 D6 that were initially encapsulated and the encapsulation of one molecule of AdA.
176

The 53rd IChO 2021 JapanReference
Practical Tasks

The 53rd International Chemistry Olympiad, IChO 2021 Japan, was held remotely,
unfortunately we were not able to do the practical exams.
In order to reinforce the importance of laboratory work, the practical tasks
prepared for the 53rd IChO 2021 Japan were made open, despite not being officiallyapproved by the International Jury meeting for the 53rd IChO 2021 Japan.
We prepared videos in which all tasks were demonstrated with explanations andpublished the videos as one of the activities during the 53rd IChO 2021 Japan.
We hope that many of you will take up the challenge of the practical tasks.

Practical Task 1. Partition coefficient of 2,5-furandicarboxylic acid in a 1octanol/water system‘Biomass chemistry’ is attracting attention as a strategy to break away from the oildependence of human society. Furan derivatives are plant-derived chemicals that can beused as building blocks for new materials. They are made from furfural, which can beeasily synthesized from agricultural waste containing sugars. One furan derivative, 2,5furandicarboxylic acid, has been extensively studied as a raw material for bioplastics.
When using a new material, it is essential to elucidate the effects of the chemical on thehuman body, animals, and plants. It is known that the accumulation of a chemical in livingorganisms is related to its hydrophobicity. The 1-octanol/water partition coefficient is oneof the best indicators of hydrophobicity/hydrophilicity.
The purpose of this experiment is to calculate the partition coefficient of 2,5furandicarboxylic acid in a 1-octanol/water
systemby examining the 2,5-furandicarboxylic
acid concentrations in the 1-octanol phase andthe aqueous phase and analyzing its aggregationstate in 1-octanol.
Chemicals
Substance

Name

State

GHS Hazard Statement

C6H4O52,5-Furandicarboxylic acid

1-Octanol
Solution(0.020mol L-1 )H319

C8H17OH

1-Octanol

LiquidH319, H412

NaCl

Sodium chloride

Aqueoussolution
(10%)

NA

NaOH

Sodiumhydroxide

Aqueoussolution(ca. 0.01
mol L-1) *H290, H314

C20H14O4

Phenolphthalein

Ethanolsolution

H226, H320

*Exact concentration will be shown at the examination.

Reference

179

Glassware and Equipment- 2 Volumetric flasks, 100 mL- 2 Pipettes- 1 Silicone dropper- 3 Erlenmeyer flasks with stopper, 100 mL- 4 Volumetric pipettes, 20 mL- 3 Volumetric pipettes, 10 mL- 1 Pipettor- 1 Laboratory stand with burette clamp- 1 Burette, 25 mL- 1 Funnel- 3 Conical beakers, 50 mL- 1 Magnetic stirrer- 1 Stirrer bar
For the procedure “Taking an Aliquot of Aqueous Phase B”- 3 Pipettes- 3 Beakers, 50 mL
Procedure
1.

2.

3.
4.
5.

Transfer two 20 mL portions of 0.020 mol L-1 2,5-furandicarboxylic acid solution(Solution A) to a 100 mL volumetric flask (total volume: 40 mL). Fill the flask with
1-octanol using a pipette. Homogenize the solution, which is henceforth called
Solution B.
Transfer 20 mL of Solution A to another 100 mL volumetric flask (total volume: 20mL). Fill the flask and homogenize the solution as above. This solution is called
Solution C.
Transfer two 20 mL portions of Solutions A, B, and C to 100 mL Erlenmeyer flasks
with stoppers (total volume: 40 mL each).
Add two 20 mL portions of 10% aqueous NaCl solution to each Erlenmeyer flask(total volume of the aqueous solution: 40 mL). Seal the Erlenmeyer flasks.
Hold each Erlenmeyer flask firmly so that the stopper does not come off, shake itvertically 30 times, and let it stand for 5 minutes. Shake the flask and let it stand 5
times in total. (In general, the partition coefficient depends on the temperature.
However, the partition coefficient does not change in the range of 20-30°C in thissystem. Therefore, this experiment can be conducted at room temperature without
temperature control.)180

The 53rd IChO 2021 Japan6.

Transfer 10 mL of the aqueous phase of Solution C to a conical beaker with a 10
mL volumetric pipette (*Refer to “Taking an Aliquot of Aqueous Phase A or B”).
Add a stirrer bar and 1 drop of phenolphthalein solution. Titrate using 0.01 mol L-1
aqueous sodium hydroxide solution with stirring. Repeat the titration as needed (thetitration can be done up to 3 times). Similarly, titrate Solution B and A in that order.

* “Taking an Aliquot of Aqueous Phase A”
a. Insert a volumetric pipette into the solution so that the tip is near the center of theaqueous phase.
b. Blow out a small amount of air using a pipettor and push out the solution at the tip.
c. Pull up the aqueous phase so that the none of the oil phase remaining on the bottom
and sides of the Erlenmeyer flask is drawn in.
d. Pull the volumetric pipette out of the solution and wipe off the solution on the outsideof the pipette.
e. Align the meniscus of the solution and the line marked on the pipette.
f.

Transfer the aqueous phase to a conical beaker.

* “Taking an Aliquot of Aqueous Phase B”
a. Insert a pipette into the solution so that the tip is near the center of the aqueous phase.
b. Blow out a small amount of air using a silicone dropper and push out the solution at
the tip.
c.

Pull up the aqueous phase (more than 10 mL) so that none of the oil phase remaining
on the bottom and sides of the Erlenmeyer flask is drawn in.

d.

Pull the pipette out of the solution and wipe off the solution on the outside of thepipette.
Transfer the aqueous phase to a beaker.
Transfer the aqueous phase from the beaker to a conical beaker using a volumetricpipette.

e.
f.

Reference

181

Results
Record the titration volume.
No.

Volume forVolume forVolume for

Solution Ａ [mL]

Solution B [mL]

Solution C [mL]1
2
3
Volume determined [mL]

*It is not necessary to fill in all rows.
Questions
1. Calculate the concentration of 2,5-furandicarboxylic acid in the aqueous phase, 𝐶𝐶𝑤𝑤 ,
and ORJ𝐶𝐶𝑤𝑤 from the determined titration volume.
Solution Ａ

Solution B

Solution C

Ｃw [mol L-1]
logＣw

2.

Calculate the concentration of 2,5-furandicarboxylic acid in 1-octanol, 𝐶𝐶𝑜𝑜 , and ORJ𝐶𝐶𝑜𝑜 

using the total amount of 2,5-furandicarboxylic acid.
Solution Ａ

Solution B

Solution C

Ｃo [mol L-1]
logＣo

3.

If 2,5-furandicarboxylic acid is present in water at a concentration of 𝐶𝐶𝑤𝑤  as a single
molecule and in 1-octanol at a concentration of 𝐶𝐶𝑜𝑜 as an n-molecule aggregate, thepartition coefficient K is calculated using the following equation.
𝐶𝐶𝑜𝑜
= 𝐾𝐾
𝐶𝐶𝑤𝑤 𝑛𝑛

Taking the logarithm of both sides, the equation can be transformed as follows:
log𝐶𝐶𝑜𝑜 = 𝑛𝑛log𝐶𝐶𝑤𝑤 + log𝐾𝐾182

The 53rd IChO 2021 Japan

Taking points A, B, and C as (log 𝐶𝐶𝑤𝑤 (A), log 𝐶𝐶𝑜𝑜 (A)), (log 𝐶𝐶𝑤𝑤 (B), log 𝐶𝐶𝑜𝑜 (B)), and(log 𝐶𝐶𝑤𝑤 (C), log 𝐶𝐶𝑜𝑜 (C)), respectively, calculate n and K from the equations of thestraight lines AB, BC, and AC, and average them. If necessary, use the graph paperon the next page.
n

K

AB
BC
AC
Average

4.

Draw the structure of the aggregated 2,5-furandicarboxylic acid that is expected to
be present in 1-octanol from the calculated value of n.


Reference

183




184

The 53rd IChO 2021 Japan

Practical Task 2. Separation and determination of metal ions using anionexchange resins
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Reference185

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186

The 53rd IChO 2021 Japan

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Reference187

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The 53rd IChO 2021 Japan

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Reference

191

Brevity isis thethe soulsoul ofof witwit inin organicorganic synthesis
synthesis.
Practical Task
Task3.3. Brevity
Introduction
In organic synthesis, C–C-bond-forming reactions to build molecular frameworks are some of themost basic yet also most important reactions. Many C–C-bond-forming reactions require large
amounts of organic solvents and complicated procedures for separation and purification of the target
compounds and are thus associated with a relatively high environmental load. In this task, a C–Cbond-forming reaction is carried out between triphenylmethanol (1) and malonic acid (2) to synthesize
3,3,3-triphenylpropionic acid (3) as shown in equation (1). This is a well-designed synthetic method
in which the reaction proceeds via the simple heating of two solid raw materials, and the target product3 can be obtained in high purity using only recrystallization without performing complicatedseparation procedures. The purpose of this task is to consider the reaction mechanism based on theexperimental results and understand the well-designed reaction system.

(1)

Chemicals
Substance

Name

State

GHS Codes(C6H5)3C–OH

Triphenylmethanol

Solid

H302

CH2(CO2H)2

Malonic acid

Solid

NA

C2H5OH

EthanolLiquidH225- H320

Glassware and equipment- 1 Erlenmeyer flask (30 mL)- 1 Hot plate with digital temperature display (or a thermometer for the surface temperature)- 1 Pipette (5 mL)- 1 Spatula- 1 Screw-top bottle (20 mL)

192

- 1

Apparatus for filtration- 1

Paper for wrapping powdered medicine- 1

Pair of work gloves

The 53rd IChO 2021 Japan

Experimental procedure
CautionIn this task, gases with low toxicity but a strong smell are generated. Perform in anenvironment where a fume hood or other air exhauster can be used appropriately.
During heating, the hot plate reaches high temperatures. Be careful to avoid burns.
1.

Set the surface temperature of the hot plate to 170 °C. Control of the surface temperature isessential. If the hot plate does not have a digital temperature display, its surface temperature
should be measured using a thermometer (such as a radiation thermometer).

2.

Add triphenylmethanol (Ph3C–OH, 1.041 g) and malonic acid (2.082 g) to an Erlenmeyer flask(30 mL) and mix the reactants by gently swirling the flask by hand.

3.

Place the Erlenmeyer flask on the hot plate at 170 °C.

4.

Heat the Erlenmeyer flask for 30 min while observing the reaction.

5.

Wearing the work gloves, remove the Erlenmeyer flask from the hot plate and place
it on a stack of Kimwipes on the workbench.

6.

Set the surface temperature of the hot plate to 120 °C.

7.

Allow the flask to cool for 1 min.

8.

Add a solution of EtOH:H2O (5/1, v/v, 1 mL) to the reaction mixture and stir the solution toinitiate crystallization.

9.

If no crystals form, rub the wall with a spatula to induce crystallization.

10. Add additional EtOH:H2O (5/1, v/v, 5 mL).
11. Place the Erlenmeyer flask on the hot plate at 120 °C.
12. After complete dissolution, move the Erlenmeyer flask onto the Kimwipes on the workbench.
13. Allow to cool for ca. 2 h. Caution: even after cooling to room temperature, the crystals continue
to grow slowly.
14. Break the crystals gently with a spatula.
15. Collect the crystals by filtration under reduced pressure.
16. Place the crystals into a screw-top bottle (20 mL) and submit the sample.

For the evaluation of the purity
1. Melting point
Pure 3,3,3-triphenylpropionic acid has a melting point of 182 °C.
2.

1H NMR spectroscopy

The methylene protons and the aromatic protons of pure 3,3,3-triphenylpropionic acid show an

Reference193integration ratio of 2:15. Use a deuterated solvent other than CDCl3, C6D6, or methanol-d4,
because the residual protons in CDCl3 and C6D6 overlap with the aromatic protons, whilemethanol-d4 causes deuterium exchange of the methylene protons in 3,3,3-triphenylpropionic acid.
3. HPLCThe main contaminant would be triphenylmethanol, which can be quantified by high-performanceliquid chromatography using a reversed-phase column such as an octadecylsilicate column.

194

The 53rd IChO 2021 Japan

Questions
1. Calculate the theoretical yield, showing the details of the calculation method. It should be notedthat the crystal water and solvent are not included.

2. Write the chemical formulae of the products X and Y that are generated by the reaction of
triphenylmethanol (1) and malonic acid (2) in equation (1).

3. Draw the chemical structure of the ionic intermediate A that is generated from triphenylmethanol(1).

4. Describe the most important experimental evidence suggesting the formation of the ionicintermediate A.

5. In this task, malonic acid plays multiple roles. Write the role of malonic acid other than as a
stoichiometric reagent and a solvent.

6. This task requires an appropriate air exhauster (such as a fume hood) for removing compound B
generated during the reaction. Write the formula of compound B.

7. The procedure in this task is well designed. If the reaction conditions are changed as described
below, what will occur?
(i) using a 1:1 mole ratio of triphenylmethanol and malonic acid to avoid using a large amount ofmalonic acid.
(ii) using a solvent for the enhancement of the reaction selectivity.
(iii) using a Liebig condenser, the generated compound B is refluxed to prevent it from leaving thesystem.
(iv) the reaction is carried out at 150 °C to implement milder conditions, or at 200 °C to enhance
the reaction rate.
To further enhance the efficiency of the reaction (e.g., yield, purity, reduced raw material

Reference

195

consumption, reduced energy consumption, reduced waste, simpler procedure), what kind of
method might you propose? Discuss this with your mentor.
“ The best is not, so long as we can say, ‘This is the best.’” – modified from King Lear.

196

The 53rd IChO 2021 Japan

Catalyzer

Catalyzer 0

Catalyzer

199

200

The 53rd IChO 2021 Japan

Catalyzer

201

202

The 53rd IChO 2021 Japan

Catalyzer 0.5

SpecialIssue

Due to the
COVID-19 pandemic,
IChO2021 Japan will
be held remotely.

June

2021
2021.7.25 (Sun) − 8.2 (Mon)
Remote examination on

7.28 (Wed)W

elcome to the IChO2021 Japan 53rd International Chemistry
Olympiad. I am delighted to serve as the Chair of the Executive
Committee of IChO2021, a very important scientific event especiallyfor students at secondary school level.

This past January, we carefully discussed whether we could holda real or remote Olympiad in 2021. We eventually decided to holda remote Olympiad this summer, owing to the ongoing global
COVID-19 pandemic. The most important priority was to be able toorganize IChO2021 safely and smoothly. Our remote IChO2021 will
be held from 25 July to 2 August, 2021. The three key concerns of the
Chemistry Olympiad are as follows: (1) The safety of all participants,
including secondary school students; (2) Equal opportunity forevery student; and (3) International experiences via competitionand cooperation, despite the Olympiad being held remotely.
I hope you have already visited our website, https://www.icho2021.
org. There you can find our motto for IChO2021, “Chemistry! It’s
Cool!”, as well as our first Catalyzer newsletter. We are sure that you
can still enjoy chemistry and experience O-Mo-Te-Na-Si during thisremote Olympiad.

The opening ceremony will be held online on our website on 25
July, 2021, and the examination will be conducted in each country
on 28 July. Students will be able to take the examination in theirhome countries. The duration of the examination is five hours. The
examination may start at any time between 4:00 pm and 9:00 pm
JST, and each country can decide the starting time that suits them.

After grading is complete, an online closing and award ceremony
will take place on 2 August. Students may attend the ceremony with
their avatars. Medals and the certificates will be sent to participants
via surface mail together with commemorative gifts.

Between the opening and closing ceremonies, Olympiad
participants can enjoy a series of remote events. These include
virtual visits to tourist spots such as Himeji Castle and otherfamous world-heritage temples and shrines in the Kansai region(Kyoto, Nara, Osaka, and Kobe). Interesting cultural events are alsoplanned, including a visit to a special site at which repair work to anancient Buddha statue is being carried out. Students can take part ina scientific virtual visit to SPring-8, the world’s largest synchrotron
radiation facility. Communications among participating students
are also important. Virtual reality avatars will be available for all
students to enhance their remote communication experiences. We
also plan to make the practical examination available to the generalpublic so they can try their own experiments.
We will make every effort to make our remote
IChO2021 Japan a resounding success. On behalfof the executive committee, I sincerely hope you
all enjoy the Chemistry Olympiad this summer.

Catalyzer

203

Q How will be the examination

conducted remotely?

Q What are the time zones for the remote IChO?
Q Where should theexamination be located?

Q When is the date for the examination?

Q How long is the examination?

Q What help/tools are allowed
for the examination?
Q What is the start time of the examination?

Q What are the important dates for the IChO2021?

Date

Jul 23, Fri

Student

Jul 25, Sun
Jul 26, Mon

Training of Oly-ExamOpening Ceremony (Start time to be determined)

MentorReceive the problem
Deadline of feedback

Activity (To be announced)

Jury meeting
Receive the authorized problem

Jul 27, Tue

Activity (To be announced)

Jul 28, Wed

Start remote examination at

Translation/submission
Deadline of translation[Invigilator] Submit the solutions (Within one hour after the end of the examination)

Receive the solution and the grading scheme
Activity (To be announced)

Aug 1, Sun
Aug 2, Mon

204

The 53rd IChO 2021 Japan(from Organizer, Request arbitration)

Deadline of request, Jury meeting
Arbitration
America(west)

Asia

EuropeReceive final results
Activity (To be announced)
Closing Ceremony▼▼▼

Jul 31, Sat

Receive grading▼▼▼

Activity (To be announced)▼▼▼

Jul 29, Thu
Jul 30, Fri[Invigilator] Receive and print out the problem

America(east)

sei

mi

kyoku

舎 密 局

D

uring the Edo period (1603 to 1868), when the Tokugawa
shoguns ruled the country, Japan adopted a policy of seclusionand closed its borders to the outside world for more than 250 years;
international trade was allowed only with China (mainly under the
Qing dynasty) and the Netherlands. Any information on the naturalsciences that emerged in Europe in the early 18th century came only

from the Netherlands through Dejima, a small artificial island in thebay of Nagasaki on the west end of Japan.

Tⓒ Tetsuo Shiba

he first systematic chemistry lectures in Japan were given

ingredient Ajinomoto (Catalyzer, No. 6), studied chemistry under

Western medicine in Nagasaki, and after he found that the students

deepened his knowledge by listening to Gratama’s lectures, andby Johannes Lijdius Catharinus Pompe van Meerdervoort,a physician who came to Japan in 1857. Pompe began teachinglacked fundamental knowledge in science, he also started teachinga course in basic science. After Pompe left Japan, Dr Anthonius
Franciscus Bauduin was invited to succeed him, and taught
chemistry as well as medicine. Following Bauduin, the Dutchchemist Koenraad Wolter Gratama was invited to teach in Japan asa specialist in science and chemistry teaching.

In 1867, Gratama was set to be transferred to the Kaiseijo, theshogunate’s Western education and research center locatedin Edo (present-day Tokyo), but this plan was thwarted when the

shogunate collapsed during the Meiji Restoration in 1868. The new

Meiji government, however, established a college called the Seimi-

the tutelage of Jiro Murahashi, Gratama’s assistant at the Seimikyoku. Hiroakira Akashi, who worked at the medical school hospital,
eventually established the Kyoto Seimi-kyoku in his home town

Kyoto, with the support of the Kyoto prefectural government. Genzo

Shimazu, a blacksmith who had been a contractor at the Kyoto Seimi-

kyoku, was taught by the German teacher there, and later established
Shimadzu Corporation, the chemical equipment manufacturer(Catalyzer, No. 5). These are just a few examples of the many

students and teachers who received direct or indirect instruction

from foreign teachers and who later drove the development of
medicine, chemistry, and pharmacy in Japan.

In 1870, Gratama completed his term of office and returned to
the Netherlands the following year. The German chemist Georg

kyoku in Osaka to replace the Kaiseijo, and welcomed Gratama as head

Hermann Ritter was invited to replace him. In 1872 however, all thegovernment’s move to establish the Seimi-kyoku in Osaka is said to have

Seimi-kyoku underwent several organizational and name changes,

lecturer there. The word seimi was a transliteration of the Dutch word

chemie, though it is no longer used today. One reason behind the new
been their initial intention to move the capital from Kyoto to Osaka,rather than to Tokyo. Ultimately, however, the Emperor moved to Edo

Castle where the Tokugawa shogunate was based, after the castle wassurrendered bloodlessly to the new government. Eventually, Edo wasrenamed Tokyo and became the new capital city of Japan.

In 1868, the new Seimi-kyoku (also known as the Osaka Seimi-

kyoku) was completed, and Gratama started teaching physics

and chemistry there. Gratama not only taught students, but also

initiated training programs for physics and chemistry teachers. The
following year, a medical schooland hospital were establishednearby,where

Bauduinalso

personnel and assets of the Seimi-kyoku were transferred to the Tokyo
Kaisei Gakko school, which later became the University of Tokyo. The

finally becoming the Third Higher School in 1889, which would later
be merged into Kyoto University. At the site of the former Osaka
Seimi-kyoku near Osaka Castle, there is a large camphor tree in acorner surrounded by a stone wall that appears to block the walkway,
and at the base of the tree stands a stone pillar and monument that

reads “Site of the Former Seimi-kyoku.” On the reverse side of themonument is a majestic bust of Gratama. Although the Seimi-kyoku

disappeared in the turbulent times for Japanese society in the early
Meiji era, its legacy lives on as the foundationof chemistry in Japan today.

taught. Many students from the

medical school also came to attend

the lectures at the Seimi-kyoku,
among them Jokichi Takamine,
who later became well-known

for his research on adrenaline(Catalyzer, No. 2). Kikunae Ikeda,
who discovered the “umami”

Catalyzer

205

Element#1T

oday, Japan depends mostly on imports of the mineral
resources it needs, but in the past it used to produce large

amounts of gold, silver, and copper. Marco Polo, the 13th-century
merchant and explorer who travelled throughout Asia, introduced
Japan to Europe as “Japan, Land of Gold” in his travelogue The

Ag

Travels of Marco Polo, which later became the driving force foradventurous explorers during the Age of Discovery.

Sado

Oda

Long ago, gold mines such as those on the island of Sado (part

Au

Koshu
Niihamaof Niigata prefecture today) and in Koshu (Yamanashi prefecture)Cu

produced significant amounts of gold. In the Edo era, from the16th to the 19th centuries, the Tokugawa bakufu (shogunate)established an official gold guild known as the Kin-za, and goldcoins called Keicho Koban and Oban were issued.

In terms of silver production, one of the major operations
was the Iwami Ginzan silver mine, where production ofsilver continued for approximately 400 years from the 16th

century. The Iwami Ginzan silver mine was located in what is thecity of Oda in Shimane Prefecture today, and production reached
its peak during the Edo period, when the mine was directly
managed by the bakufu. Production then gradually decreased

until the mine was closed in 1923. The Iwami Ginzan silver minesite was registered as a UNESCO World Heritage (Cultural) Site
in 2007, listed as the Iwami Ginzan Silver Mine and its CulturalLandscape, with special mention made of its environmentallyfriendly operation.

206

The 53rd IChO 2021 JapanT

he Besshi copper mine located in what is the city of Niihama
in Ehime Prefecture, discovered in 1690, produced a total of

700,000 tonnes of copper in 283 years until it was closed in 1973.
The former mine site is now the location of Minetopia Besshi, ahistorical theme park where people can learn how the mine
operated in the olden days.

Catalyzer 1No.

1Jul. 25

2021

I

t is our great pleasure to host the 53rd International Chemistry
Olympiad (IChO2021), a competition so rich in history since
the first one in 1968, and to welcome very talented young students
from 79 countries and regions around the world.
As important as it is as an academic subject, chemistry is also thebasis for creating materials and substances with a vast range offunctions that constantly supports our daily lives.

The COVID-19 pandemic is still plaguing the world. Chemistry is
playing a vital role in the fight against COVID-19 by being applied
for PCR and antigen testing to detect infection and its history andfor the manufacture of COVID-19 treatment drugs.
Moreover, we expect chemistry to greatly contribute to achieving
the Sustainable Development Goals, including the stable supply offood, the recycling of waste, and so on.

All the students participating in IChO2021 have the potential
to address these various shared problems of the world andto open up a new path for humankind. It is a crucial issue forgovernments around the world to discover their talents and create
an environment to develop fully these capabilities.

capabilities. As the host country, Japan will make its utmost efforts
to support this mission.

Because of COVID-19, like the previous Olympiad, IChO2021 will
be held online. The organizers are planning to make full use of VR
technology and avatar technology to provide remote tours to bothstate-of-the-art and traditional science and technology facilities,
which large groups of people cannot usually visit. Unfortunately
you will not be able to have direct interaction, however, with thecreative use of these technologies, you will be able to overcome thebarriers of distance and space to connect with your peers.

We hope that all of you representing your countries at thisOlympiad will fully demonstrate your real abilities and the resultsof your efforts, improve yourselves through competitions, andmake lasting friendships with peers.
It is our sincere wish that you all continue yourself-improvement and make the most of yourexperiences to play active roles in leading
your countries and the world.

The International Science Olympiads, including IChO, haveprovided various opportunities for talented students to challenge,
and contributed to discovering such students and fostering their

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207

IChO2021 JapanI

am Kohei Tamao. Thank you for your kind introduction. It isa great pleasure and honor for me to say a few words at the
opening ceremony of the 53rd International Chemistry Olympiad,
IChO2021 Japan.

Dear talented high school students, mentors, scientific observers,
guests, distinguished scholars, invigilators, Steering Committee
members, and colleagues from all over the world, welcome to theOpening Ceremony of IChO2021 Japan.
Originally, we had been preparing to hold IChO2021 Japan at
Kindai University, one of the biggest private universities in Japan,
located in the lively and modern commercial city of Osaka in midwest Japan, also known as the birthplace of chemical research inthis country.
However, in light of the ongoing COVID-19 pandemic, we had
no choice but to hold IChO2021 remotely, following the lead of
IChO2020 Turkey last year.
This is the result of giving top priority to the safety of ouryoung talented students and all participants, even at the expenseof practical examinations and opportunities for in-person
international exchange. I would like to thank all the International
Steering Committee members led by Dr. Gábor Magyarfalvi for
their enthusiastic discussion and acceptance of our decision.
Even under the difficult conditions presented by the COVID-19
pandemic, the good news is that we have accepted registrations
from 85 countries and regions of the 89 to which we sent
invitations. More than 320 students have been registered. I would
like to express my sincere gratitude and respect for the wonderful
efforts of mentors, teachers, and all concerned in each country to
select talented students and set up the examination sites.
The theoretical examinations will be held on July 28th in eachcountry, and the examination results, including gold, silver andbronze medalists, will be announced in the closing ceremony on
August 2nd.
I am confident that the remote examinations on July 28th will
be carried out in an atmosphere of justice, fairness, and trust,
maintaining the spirit of IChO across space and time. It is mysincere hope that all the participating students will do their very
best, showcasing the talents and skills they demonstrate every day.
As we are unable to hold the practical examinations, we have
prepared a demonstration video of the practical tasks.
To compensate for the fact that the participants cannot meetin person, we will offer various initiatives for students to create
international friendships and become familiar with Japaneseculture and the state of art, science, and technology in this country.
For that purpose, VR avatars for all students have been preparedto facilitate remote networking and to give greater realism tovirtual visits to sensitive areas such as the restoration site ofan ancient Buddha statue and the world’s largest synchrotron
radiation facility, SPring-8, to which access is normally prohibited.

208

The 53rd IChO 2021 Japan

Dear students, now I would like to ask you to keep the following
three things in mind, as you are about to enjoy a once-in-a-lifetime
valuable experience.
First, you have been given hope and courage to overcome difficulties
through your participation in this remote IChO2021 Japan.
Second, the unprecedented difficulties we have been facing canonly be overcome by international friendships and trust. Thus,
you should show gratitude and respect to your mentors, teachers,
invigilators, and all others who have contributed to make this majorinternational event a reality, despite the obstacles faced.
Third, I want you to remember that chemistry, the central science,is all around us. Chemistry must therefore play a key role in finding
solutions for many global challenges, including energy, environmental,
and resource-related issues that humanity is now facing.

I hope that IChO2021 Japan helps to foster many talented young
people who will go on to play roles as future world leaders. While you
do not have the opportunity to meet each other in person this time, I
am convinced that one day you may meet each other somewhere in
the world when you go to university or graduate school. I sincerely
hope that you take the opportunities given to you as participants inthis remote IChO2021 to create strong networks of international
friendship, with the slogan “ Chemistry! It’s Cool!” as your watchword.

Finally, I would like to thank the Ministry of Education, Sports,
Science and Technology (MEXT Japan) and the Japan Science andTechnology Agency (JST) for their meaningful support, and the morethan 180 chemical companies and trading companies in Japan as
our sponsors for their substantial financial assistance, as well as
numerous personal donations.
My special thanks are also due to all the members of the Japan
Committee and Organizing Committee for IChO2021 Japan, as wellas our secretariat and KNT Corporate Business Company, Ltd., asrepresented by the Vice President of the Japan Committee and Chairof the Fundraising Committee Dr. Kyohei Takahashi, Chairs of the
Finance Committee the late Dr. Tadao Kondo and Dr. Teiji Koge,
Chair of the Executive Committee Professor Yoshiki Chujo, Chair of
the Scientific Committee Professor Hiroshi Nishihara, and memberof the International Steering Committee Professor Nobuhiro Kihara.
Without their remarkable support and endeavors, this remote
IChO2021 Japan would not be possible.
Now, it is my great pleasure to officiallydeclare remote IChO2021 Japan open.
Thank you very much for yourkind attention.

DateOpening Ceremony (Virtual Reality Venue)
VR Closed

Jul 26, Mon

VR Closed

Jul 27, Tue

VR Closed

Jul 28, Wed

Examination (5 hours)

15:00

08:00

02:00

Receive the problem

21:00

14:00

08:00

Deadline of feedback

09:00

02:00

20:00

Jury meeting

21:00

14:00

08:00

09:00

02:00

20:00

Deadline of translation

09:00

02:00

20:00

[Invigilator] Receive and print out the problem

11:00

04:00

22:00

Receive the authorized problem

Translation

submission[Invigilator] Submit the solutions (Within 2 hours after the end of the examination)

Receive the solution and the grading scheme

Jul 29, Thu

Video:
Practical Examination explanation

Receive grading(from Organizer, Request arbitration)

Deadline of request, Jury meeting

Activity
Video:History and Culture of Nara

America (west)

Aug 1, Sun

Activity

Receive final results▼▼▼

Arbitration

Asia

▼
▼
▼

Jul 31, Sat

Aug 2, Mon

09:00

02:00

20:00

09:00

02:00

20:00

21:00

14:00

08:00

09:00

02:00

20:00

09:00

02:00

20:00

21:00

14:00

08:00

Activity (SPring-8 Virtual tour)

Europe▼▼▼Jul 30, Fri

Mentor▼▼▼Jul 25, Sun

Student

America (east)

Activity Video:Himeji Castle, Osaka, and Kyoto

Video:Himeji Castle, Osaka, and Kyoto

Closing Ceremony (Virtual Reality Venue)

01

H

ow do chemical reactions occur? For chemistry students,
the frontier orbitals called HOMO (Highest Occupied

Molecular Orbital) and LUMO (Lowest Unoccupied MolecularOrbital) are extremely important. This concept of frontier orbitals

was conceived by Kenichi Fukui, who in 1952 proposed thatelectrophilic substitution reactions in aromatic hydrocarbons

occur at the position with the highest coefficient of HOMO,

while nucleophilic reactions are determined by the coefficientof LUMO. This was an epoch-making

concept, completely different from theconventional theory of organic electronics,
which was based mainly on electron density.

Photo by Kagaku-Dojin

Dr. Kenichi Fukui( 1918-1998 )In 1964, he further developed this theory by pointing out thatthe symmetry and phases of the HOMO and LUMO of the reacting
molecule play important roles in cycloaddition reactions such as

the Diels–Alder reaction. In 1981, he was awarded the Nobel Prizein Chemistry for “the theories concerning the course of chemical
reactions,” together with Roald Hoffmann, who separately

published the Woodward–Hoffmann rules in 1965. Fukui was thefirst Japanese chemist and Asian person to be awarded the prize,
which had until then been won by researchers from Europe andthe United States. Today, the concept of HOMO–LUMO is widelyused not only in chemical reactions and physical properties ofmolecules themselves, but also in molecular electronics, organic

electroluminescence, enzymatic reactions, and electron transfer
in interactions in biomolecules such as proteins.

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209

Doshomachi

1“Medicine Town” and Sukunahikona ShrineFor certain infectious diseases, it is empirically known that oncea person is infected they will not contract the disease again. ThisIn the era of Toyotomi Hideyoshi (1537 to 1598), drug

wholesalers were concentrated in the Doshomachi area ofis due to the function of the immune system, which remembers the

Osaka in accordance with the government’s commercial policy.

function. Less virulent viruses or bacteria, as well as a portion ofand Holland. Drug wholesalers who imported drugs from thosedisease they have been infected with and can quickly eliminate thepathogen on the second infection. Vaccines make use of this biologicalthe pathogen (protein or polysaccharide), can be administered as a

vaccine. This allows the immune system to remember the pathogen
and prevent infection. Vaccines against COVID-19, a new type ofcoronavirus, which has had a major impact on our lives since 2020,are being vigorously developed around the world, resulting in thedevelopment of mRNA vaccines. Unlike conventional vaccines, mRNA

vaccines deliver mRNA, the gene for the pathogen protein, into thehuman body. Although mRNA vaccines have been studied since the1990s, they have not been put to practical use due to a number ofdrawbacks, including the following: 1) mRNA is not stable in vivo, 2)

mRNA is not very efficient in the production of proteins, and 3) it is
not easy to deliver mRNA into cells. Development of effective mRNA

During the isolationist period of the Tokugawa shogunate (1603
to 1867), exchange with foreign nations was restricted to China

two countries established their businesses in Doshomachi,
forming an officially approved guild, or Kabunakama, called theYakushunakagainakama. In 1721, the Tokugawa government
established an agency in Doshomachi for checking the quality of
medicinal products made in Japan (Wayakushu aratame kaisho).
Hence, all medicines commercially traded throughout Japan

passed through Doshomachi first. All these historical connections
led to Doshomachi being home to many pharmaceuticalcompanies, making it Japan’s first “medicine town,” followed laterby Nihonbashi Honcho in Tokyo.

vaccines proceeded by solving these issues one by one. This was done
through introducing artificial structures into the mRNA to prevent

degradation by metabolism, and optimizing the RNA sequence toincrease the efficiency of conversion into protein. Furthermore, by
encapsulating the mRNA in lipid nanoparticles, researchers succeededin efficiently delivering it into the cell. As a result, an extremely effective
vaccine against coronaviruses has been developed.

T

he Doshomachi Pharmaceutical and Historical Museum(Kusurinomachi Doshomachi Shiryokan) is a great place to

see exhibits of prescription medicines, instruments, equipments,and other related items used by medical wholesalers. The
Sukunahikona Shrine, a Shinto shrine that is dedicated to medical
deities, can also be found in Doshomachi.

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The 53rd IChO 2021 Japan

Early Bird Communication
United Arab Emirates

GeorgiaTo
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Cat

VietnamSweden (Sverige)

Kazakhstan

Croatia
Bulgaria

Indonesia

Nigeria

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211

F

ollowing on from the useful Japanese phrases introduced in
Catalyzer No. 0, this edition features Kansai-ben, a dialect

spoken in the Kansai region, where we had originally planned tohold the in-person IChO2021. Let’s all try speaking Kansai-ben!

In ancient Asia, tigers were considered to be messengers fromthe Gods, and their bones were used as a medicine and in lucky

Standard
Japanese

Kansai
Dialect

Good bye

Sayounara

I'm sorry.

Gomennasai Sunmahen すんまへん

My bad.

Gomen

Suman

すまん

Thank you!

Arigatou

Ohkini

おおきに

Yes

Hai

Soya

そや

Sainara

さいなら

No

Iie

Chau

ちゃう

was sweeping the world at the time, an apothecary in Doshomachi,

foolishbakamitai

ahokusa

あほくさ

nonsensekudaranai

shoumona しょうもな

Hariko-no-tora, meaning a papier-mâchéstrangeokashina

kettaina

because～ nanode～ yasakai 〜やさかい

tiredtsukareru

shindoi

しんどいHow about? Dou?

Donai?

どない？

McDonald's Mac

Makudo

まくど

FatherTousanOton

おとん

Mother

Kasan

Okan

おかん

charms. In 1822, when Osaka was hit by the cholera epidemic that
Osaka, created a Japanese herbal medicine containing tiger skulls

and distributed it with a tiger-shaped charm made of paper called
tiger. Although the medicine itself
became obsolete, Hariko-no-tora
are still handmade as traditional
crafts. They are popular in the

Kansai region as lucky charmsthat protect people from disease

and express the wish for healthy
growth of children.

ELEMENT

QUIZ

Q1

212

English

1

2

3

4

The 53rd IChO 2021 Japan

けったいなCatalyzer 2No.

2Jul. 26

2021

02

S

ome organic compounds exist as two stereoisomers thatare mirror images of each other (chiral molecules); therelationship resembles that of a person’s right hand and left hand.
Many chiral molecules are found in nature, typical examplesof which are the amino acids that make up proteins in livingorganisms. Interestingly, proteins inliving organisms are composed of only

one of the mirror-image isomers (L-typeaminoacids).

Since

livingorganisms

Photo by Kagaku-Dojin

Dr. Ryoji Noyori( 1938- )distinguish chiral molecules, asymmetric synthesis is extremely
important in the development of pharmaceuticals, flavors, andfood additives. Ryoji Noyori developed unique chiral phosphorus
ligand BINAP as a source of chirality essential for the synthesisof chiral compounds. BINAP has a beautiful structure with C2

symmetry, and its metal complexes enable various catalytic

asymmetric reactions. One of the best known applications of

BINAP is the Rh-BINAP-catalyzed asymmetric hydrogen transfer

reaction, a key step in the synthesis of (−)-menthol used in flavors
and pharmaceuticals. This technology has been commercialized
by Takasago International Corporation (Japan), a world leader

in the fragrance and flavor industry. For developing such a truly
practical method for catalytic asymmetric synthesis, Ryoji Noyori

was awarded the Nobel Prize in Chemistry in 2001, together with
William S. Knowles and Karl Barry Sharpless.

Catalyzer

213

Dr. Kohei Tamao

HAGIUDA Koichi214

The 53rd IChO 2021 Japan

Dr. Akira Yoshino

Chemistry ! It's Japan !

The Discovery of Umami
Component
Kikunae IkedaO

ur sense of taste includes sweetness,sourness, saltiness, and bitterness aswell as umami. The umami component

eld throughout the country, many of Japan’s festivals are

religious events. The Tenjin Festival in Osaka, the Gion

Japan’s three top festivals; two of them in the Kansai region ofthen, the taste was thought to consist of

western Japan. The Tenjin Festival is held at the Osaka Tenmangu

a combination of four tastes: sweet, sour,

Shrine, which enshrines Sugawara no Michizane, a 9th century

salty, and bitter. Ikeda believed that dashi

contained ingredients that made people feel Dr. Kikunae Ikeda
that a food was delicious. Motivated by thisH

2

Festival in Kyoto, and the Kanda Festival in Tokyo are known as

was discovered by Kikunae Ikeda. Backor broth made of dried bonito flakes and kelp,

Tenjin Festival
and Gion Festival( 1864-1936 )somewhat unique Japanese sensibility, he

attempted to identify the source of umami from kelp, and in 1908,
determined that monosodium glutamate was indeed the umami
component. Although glutamate itself had already been described asa chemical compound, Ikeda was the first to formulate the conceptof glutamate as a component of umami. Based on this discovery, thecompany Ajinomoto was established, which has grown to become
one of Japan’s leading food companies. Ikeda also discovered theumami component of bonito, and together with his student Shintaro
Kodama, discovered inosinic acid as the second umami component.
Whether umami is a taste or not has been debated for a longtime, but the discovery that the taste buds on the tongue containsensors (glutamate receptors) that sense umami as well as thescholar and politician. On the night of July 25, the anniversary ofMichizane’s death, a boat procession is held on the Okawa River,accompanied by a fireworks display. It is known as the festival offire and water because of the splendid sight of bonfires, lanterns,

and fireworks reflected on the Okawa River. Aside from thefestival, the Osaka Tenmangu Shrine also attracts students whocome to pray for success in their entrance exams, as Michizane

is worshipped as the god of learning. The Gion Festival has been
held at Yasaka Shrine
since the 9th century.
Thirty-two large floats

called Yamahoko areparaded through thecenter of Kyoto on July
17 each year.

other four tastes has scientifically proven that humans can actuallysense umami as a taste.
The Japanese word umami

has now gained currency
in English and has become
internationally recognized.

Tale related to
Preparatory Problem
Plactical Task 4

Catalyzer

215

Short short from Kansai

Illumination of Tsutenkaku TowerAs the COVID-19 pandemic continues to rage around theworld, Japan too is battling waves of cases and new variants,

and has started vaccinating its population in stages. Tsutenkaku
Tower, the symbolic tower of Osaka, lights up in different colors tocall on the local citizens to help prevent the spread of the disease.
In accordance with the model adopted by the Osaka prefectural

government in its countermeasures against COVID-19, the color
is red during a state of emergency,
yellow when an alert is issued, andgreen when the alert is lifted. The
tower has also been illuminated withblue lights to express gratitude to the
Welcome to IChO! I hope you are enjoying your virtual stay inJapan and getting ready for the exam. More than anything, however,

medical personnel who are strugglingon the front lines.

enjoy your time with participants from other countries. I mademany lasting friendships in IChO and I am sure you will too! Whenyou hesitate to talk with someone because they speak a different

language or come from a different culture, remember your passion
for chemistry will be the bond that connects
you together. Have fun!

4

ELEMENT

QUIZ

Q2

216

1

2

3

4

The 53rd IChO 2021 Japan

Catalyzer 3No.

3Jul. 27

2021

Catalyzer

217

Natural Product Chemistry that
Leads to Medicines Satoshi Omura

Nobel Prize
Research fromJapan 03N

ature is host to countless compounds that can be used as

medicines and yet remain undiscovered by humans. SatoshiŌmura has isolated and determined the structures of many
useful natural organic compounds produced by microorganisms
in soil, many of which have been put to practical use. One suchcompound is avermectin, a substance produced by the bacterium

Youyou Tu for “their discoveries concerning a novel therapy
against infections caused by roundworm parasites.” Youyou Tu
also discovered artemisinin, which is the basis of a group of drugs
used to treat malaria.

Actinomycetes that was isolated from the soil of a golf course

in Shizuoka Prefecture. Ōmura’s research in collaboration
with William C. Campbell showed it has strong activity as ananthelmintic, a treatment for parasitic diseases. Subsequently, a

structurally modified version of this compound, ivermectin, wasdeveloped as an anthelmintic for livestock.

Furthermore, ivermectin has been shown
to be effective against onchocerciasis, adisease which may lead to loss of sight,
caused by filarial nematodes transmitted
by mosquitoes in Africa and other tropical

Photo by Satoshi Ōmura

Dr. Satoshi mura
( 1935- )regions, and is now widely used as ananthelmintic. The 2015 Nobel Prize inPhysiology or Medicine was awarded to
Satoshi Ōmura, William C. Campbell, andChemistry ! It's Japan !

Studies on Urushiol
resin obtained from the sap of the lacquer tree and consists mainlyAstarting point for the development of organic chemistry in Japan.

he finally determined that urushiol exists

U

Rik Majima

rushi lacquerware is one of Japan’s well-known traditional

crafts. Urushi, which has a beautiful black luster, is a naturalof a catechol derivative called urushiol. The structure of urushiol was

determined by Rikō Majima, and the research process became theWhen Majima started his research around 1900, chemistry in Japanwas still in its infancy, and there was a serious shortage of skilled
chemists to guide experimental research. Majima studied organic
chemistry almost entirely on his own and became acutely awareof the gap in ability between Japan and theWestern countries; at the same time he cameto the conclusion that if he could conduct

research on lacquer, which is native to the
Orient, he would be able to develop his own

original research without being outdone byresearchers from other countries.

218

The 53rd IChO 2021 Japan

fter studying in Germany, Majima
began to determine the structure ofurushiol in earnest at Tohoku Imperial
University. With the latest European

methods such as advanced vacuum

distillation, ozonolysis, and catalytic

reduction, he tried to determine thestructure of urushiol. After several steps,

as a mixture of the compounds shown in

Dr. Rik Majima( 1874-1962 )the figure. Majima began to determine the structures of many othernatural products found only in the Orient such as indole and aconite
alkaloids, in addition to urushiol, and trained many of his students

as organic chemists. His students eventually established organic
chemistry laboratories at universities around the country and laid
the foundation for modern organic chemistry in Japan.

Tale related to
Preparatory Problem
Theoretical Task 23
Michiyo Tsujimura
Photo by Okegawa City

Himeji Castle

H

3

Saudi Arabia

imeji Castle (or Himeji-jo in Japanese) is an excellent

surviving example of a modern Japanese castle. Described

as a Hirayama Jo in Japanese, meaning a hilltop castle, it is locatedin the north of present-day Himeji. It is one of the original 12

castle towers (tenshu) which were built in the Edo period (1603
to 1868), and is designated as one of the 100 Great Castles inJapan. Himeji Castle was designated as a National Treasure in
1951, and a UNESCO World Heritage Site (Cultural) in 1993; sobecoming Japan’s first cultural World Heritage Site. The present

castle tower was built in 1609 by Ikeda Terumasa, a warlord who
married Tokuhime, the second daughter of Tokugawa Ieyasu,

MexicoIcelandthe founder of the Edo bakufu (shogunate). The castle is also
known fondly as Shirasagi-jo (White Egret Castle), as its elegant

figure resembles an egret with its wings outstretched. The castle

is characterized by brilliant white stucco exterior walls andfeatures a huge tenshu (main tower) with five layered roofs andseven stories (one underground and six above ground), which isinterconnected with smaller towers (the East, the West, and theNorthwest) by watari-yagura roofed passages. The tenshu wasrestored to its current beautiful condition after five-and-a-halfyears of restoration work that stretched from 2009 to 2015.

PolandCatalyzer

219

Element#2

I

Japanese mineral resources

Iodineodine, with atomic number 53 and an

atomic weight of 126.9, is represented by

the symbol I. It belongs to Group 17, the halogen group, together withelements such as bromine, chlorine, and fluorine. Although Japan isusually characterized as a country poor in natural resources, it isplaced second in the world after Chile in the production of iodine.

Eighty percent of iodine is produced from sodium iodide dissolved inancient seawater in natural gas wells in Chiba Prefecture. Japan evenNot just IChO, but even the months

leading up to it, are like a dream cometrue. Not only are you stimulated
intellectually but you get to meet

remarkable people at truly amazing

places in the world. The knowledge,

the drive, and encouragement you takeaway are unparalleled and stay with you
for life.

exports iodine to other countries around the world.

I

odine is a dark purple solid at room temperature and 127I is its
only stable isotope, with a natural abundance of almost 100%.

The isotope 131I is a fission product of uranium and other radioactive

elements, and it has a half-life of around 8 days transforming 131Xewith beta and gamma emissions. Therefore, stable 127I can be used

to protect people from health hazards caused by a nuclear accident.

Iodine as an element has a variety of uses in our lives such as X-ray
contrast agents, bactericidal disinfectants, and polarizers used inscreens of LCD TVs, PCs, and smartphones.

S

ince iodine is a component of thyroid hormones, a shortage of iodinein the body may lead to the condition known

as hypothyroidism. However, such shortages arerare in Japanese because the country is surroundedby sea and sufficient iodine can be obtained from a

Answer for Q2
4diet rich in seaweed and a variety of seafoods. By
contrast, many people living in other parts of theworld are exposed to the risk of iodine deficiency.

Thus, potassium iodide or potassium iodate isadded to the table salt to prevent it.

ELEMENT

QUIZ

Q3

220

The 53rd IChO 2021 Japan

1

2

3

4

Catalyzer 4No.

4Jul. 282021

H

ello, everyone. This is Akira Yoshino.
Congratulations to all the representatives from all over
the world who participated in the 2021 International Chemistry
Olympiad in Japan. I congratulate you on your daily interest inchemistry and the fruits of your enthusiastic learning. We would
also like to extend our congratulations and respect to the mentors
from each country who have nurtured such wonderful athletes.

The International Chemistry Olympiad is an international eventin which high school students from all over the world compete for
their chemistry skills. Not only that, but it also builds a humanresources network for young people through international
exchange and deepens their understanding of Japanese culture. It
will be of great significance to develop human resources who will
be in a leadership position in the future.
Unfortunately, due to the influence of the new coronavirus
pandemic, it has become a remote competition, but even in such adifficult situation, it is the relationship of international trust thathas been built up so far. I would like to once again recognize withyou that it is supported by the depth of friendship, and I would liketo express my sincere gratitude to all the people concerned and theexecutive committees of each country for their efforts.

I received the Nobel Prize in Chemistry in 2019 for developing alithium-ion secondary battery and leading it to practical use. In thisdevelopment, after a long basic research based on the propertiesof lithium, cobalt, carbon, etc., it was put into practical use. In thisway, the results of basic research in chemistry have the power tochange the social system. Chemistry must play a leading role insolving various problems such as environment, resources, energy,
and health that are currently facing on a global scale. And they are
entrusted to a younger generation like you.
You are the leaders of each country and the world in the future.
Please take pride in participating in the International Chemistry
Olympiad, and remind yourself of the importance of these roles inchemistry for further development.

Please do your best in the written test and enjoy the VR videos
of various research facilities and cultural activities
that are prepared to deepen your exchange.
This is my greeting.

Chemistry is central science. It plays an important role in creating
new substances by making full use of the properties of elements.

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221

Nobel Prize
Research fromJapan 04

L

Development of Lithium-ion
Secondary Batteries Akira Yoshinoithium-ion batteries (Li-ion batteries) are used in all aspectsof modern life, from small smartphones and notebook

computers to electric vehicles, due to their features such as lightweight, rechargeability, and high capacity. It would not be an

exaggeration to say that Li-ion batteries enable us to freely carry

to pursue chemistry by the book “THE CHEMICAL HISTORY OF

A CANDLE”, written by Michael Faraday, which his homeroom
teacher in elementary school recommended he read.

electricity around. It all started in 1976 when Stanley Whittingham
developed a revolutionary rechargeable battery using metallic

lithium for the anode and titanium disulfide for the cathode,which intercalates lithium ions. Later, John B. Goodenoughdeveloped a battery using lithium-cobalt oxide (LiCoO2) as thecathode, but the practicality of this battery was challenged by
the fact that it used metallic lithium as the anode, which posed

the risk of explosion and ignition. Akira Yoshino(photo: previouspage) overcame these safety and stability issues by using carbon
materials for the anode, and laid the foundation for practical

Li-ion batteries. For these achievements, Akira Yoshino, John
Goodenough, and Stanley Whittingham were awarded the Nobel

Prize in Chemistry in 2019. Akira Yoshino was born and raised in

Osaka, where IChO2021 was to be held. He says he was inspired

Tale related to
Preparatory Problem
Theoretical Task 10
Universal indicators are widely used to check the pH values ofaqueous solutions. Nowadays, the most popular universal indicatorshows red in acidic conditions and blue in basic conditions, thesame color variation as that of the rainbow and therefore easy toremember. Is there a suitable molecule that will show such a drastic
color change alone? The answer is no: universal indicator is a
mixture of several indicators. The original recipe was proposed bya Japanese researcher, Shinobu Yamada, in 1933. Let’s see how
he cleverly mixed the individual indicators to achieve a rainbow ofcolors. Thymol blue (TB) changes from red to blue via yellow. To
generate the color orange, methyl red (MR) is added. Because of
the pKa gap between TB and MR, we can generate an orange color,which is the mixture of red (MR) and yellow (TB), around a pH of 3
to 4. Bromothymol blue (BTB) is used to generate a green color.
Using the pKa gap between TB and BTB, we can generate green,
which is a mixture of yellow (BTB) and blue (TB), around a pH of 7
to 8. Note that MR in basic conditions and BTB in acidic conditions
are yellow. Therefore, too much MR makes the solution green inbasic conditions, and too much BTB makes the solution orangein acidic conditions. Fortunately, phenolphthalein (PP) is colorless

222

The 53rd IChO 2021 Japanin acidic and neutral conditions, and therefore the purple color inbasic conditions can be adjusted relatively easily. The appropriate
constituent ratio is determined by human eyes with a trial-and-error
process. We are thankful for Yamada’s keen eyes that gave us thisuniversal indicator today.

Chemistry ! It's Japan !

Spectrochemical SeriesG

ems and pigments have attracted human beings with theirbeautiful colors since ancient times. Such colors are mainly

caused by transition metal ions: the colors depend on not only

types of metal, but also the ligands attached to the metal, and thecoordination structures. However, the colors we see are mere
sensory expression, which differs from individual to individual.

Thus, quantifying the colors derived from inorganic compounds

as energy and understanding the causes of these colors has been amajor challenge for complex chemistry.

C

omplex chemistry was first brought to Japan by Yuji Shibata(1882–1980), who learned from Alfred Werner, the founding

father of modern complex chemistry, and later taught at Tokyo

Imperial University and Nagoya Imperial University as a Professor.

His student Ryutaro Tsuchida, who later taught as professor at Osaka

Imperial University, became interested in the relationship between

color and ligands in metal complexes. After conducting measurementof the electronic absorption spectra of a numerous kind of metal
complexes, he discovered a quantitative relationship between the
wavelength of the absorption band and the ligand. Based on thisRyutaro Tsuchidafinding, he proposed the spectrochemical
series (1938), in which ligands and metal
ions are arranged in the order of theenergy difference of the d-d transition ofoctahedral metal complexes. Later, it wastheoretically supported by ligand field

theory, which considers the covalent natureof the metal–ligand bond, and it became Dr. Ryutaro Tsuchida( 1903-1962 )clear that the spectrochemical series is anorder of ligand field splitting energies. In addition to colors, Tsuchida

was also strongly interested in the steric structure. He assumed thecoordination bonds in complexes to be in the same bonding stateas the covalent bonds in organic compounds, and the most stablemolecular structure is the one that minimizes the repulsion between
all electron pairs. This model that Tsuchida conceived was actuallyalmost the same as the model known as the VSEPR rule today;

however, this would not be known globally, since Japan was at midstof war. This achievement is very typical of Tsuchida, we may say,
who was always conscious of correlations between “structure andproperties” of complexes.

In addition to his chemical research, Tsuchida also devoted
himself to the expansion of chemical education as well as his

own research. He was involved in producing teaching guidelines
for high school chemistry and handbooks to chemical experiments,and he was also involved in launching and publishing chemicalmagazines for general public. In particular, he was a long-timemember of the editorial board of the monthly magazine “Kagaku(Chemistry)” (first published in 1951) : this periodical is still

published today, and the logo he designed for the magazine is stillused as company logo of Kagaku-Dojin.

4F

Fushimi Inari Taisha Shrine

ushimi Inari Taisha, also known as Oinari-san, is the mostimportant of the Inari shrines that are dotted throughout

Japan, and is located in Fushimi-ku, Kyoto. Since the shrine wasestablished in 711, it has been worshipped as a god of good
harvest, prosperous business, safety in the home, and fulfillmentof wishes. The foxes that serve as messengers of the shrine arealso cherished by the people. From the first torii gate on themain approach to the shrine, the outer hall of worship (maiden),inner hall of worship, and main hall of worship are arranged in astraight line. It is said that there are about 10,000 torii contributedby followers, including the beautiful vermilion senbon torii (onethousand gates) that line the mountain. Fushimi Inari Taisha is oneof the most popular tourist spots among people visiting Japan.

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Early Bird Communication
Slovenia

TurkeyT
CataGermany

Azerbaijan

United States of America

Pakistan
Bangladesh224

The 53rd IChO 2021 Japan

Japanese mineral resources

Element

Lithium#3

Hello, dear Olympians! My name is Edith Leal and I representedL

the mexican delegation in the 45th and 46th IChO and now I’m

LiAlSi2O6

studying my PhD in Chemistry. Looking back from the future, thebest advice I can give to you is to give your personal best. Meetingso many young people, who are very intelligent and who seembetter prepared for the tasks than you can be very overwhelming,

however, remember that just by being here, you have already won a
lot of knowledge, from the fundamentals of Chemistry, beyond your1

usual high school program, to the very specialized Preparatory

Problems, which some of them are so specialized, they can bedifficult to encounter, even as an undergraduate Chemist. So, stopworrying about anything else and focus into putting everything you

know on the questions in the exam, so that when you finish, you feelsatisfied and happy with yourself.

Greetings and my very best wishes!

ELEMENT

QUIZ

Q4

1

2

3

4

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5Jul. 29

2021

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Soft Laser Desorption for Mass
Koichi Tanaka
Spectrometry
上の４コマ：化学会館 7/28 試験会誌後 日本チームの４人の試験受験風景
Nobel Prize
Research fromJapan 05

R

ecent years have seen a growing need for methods to determine
the structure of biomolecules such as proteins, carbohydrates,

and lipids. Koichi Tanaka, an engineer at Shimadzu Corporation, hasdeveloped an innovative method to enable mass spectrometry ofsuch large biomolecules. Mass spectrometry (MS) is an analyticalmethod for measuring the mass of a material in its ionic state, basedon its mass-to-charge ratio, and to do this, the sample (analyte)

must first be ionized. Previously, electron ionization (EI), in which

the sample is irradiated with thermal electrons, was mainly used
for this process, but this did not provide useful information on themass of biological macromolecules with high molecular weights
such as proteins, because they are hard to volatilize and are easily

decomposed by heat. On the other hand, inthe soft laser ionization method such as thematrix-assisted laser desorption/ionization(MALDI) method, the analyte is mixed witha viscous liquid known as a matrix andirradiated with an ultraviolet laser beam,

which causes rapid heating and ablation of

the matrix as well as vaporization and ionizationof the sample, enabling a soft ionization of the

Photo by
Shimadzu Corporation

Dr. Koichi Tanaka( 1959- )analyte. It is said that this method was conceived when a sample

was mistakenly prepared using glycerin instead of acetone, and thesample was analyzed so as not to waste it. This method becomesa particularly powerful tool when analyzing compounds with large
molecular weights, making it possible to measure compounds withmolecular weights of 100,000 or more. MALDI, and another method
known as electrospray ionization (ESI), developed by John B. Fenn,

are currently the main methods used for ionizing organic compounds
for mass spectrometry. The 2002 Nobel Prize in Chemistry was

下の 3 コマ：都ホテル

7/28

awarded “for the development of methods for identificationand structure analyses of biological macromolecules” to Koichi

試験中の国が多い時間帯
監視しているシーン
Tanaka, John B. Fenn,
and Kurt Wüthrich for their achievements

in protein structure analysis. This particular year’s Nobel Prize in
Chemistry was unique in that it was awarded for the development offundamental technologies that support advanced research.

Remote Examination on Jul. 28

BACKSTAGE
of Examinationin Kyoto

watching
the exam...

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Chemistry ! It's Japan !

Akashi Kaikyo Bridge

New Nomination Nh
to Periodic Table

113

N

nihonium and the symbol Nh were officially ratified in November

T

Western countries. Nihonium (278Nh), was artificially synthesized byanother suspension bridge called the Onaruto Bridge that crosses

ihonium is the 113th element (symbol: Nh) of the periodic table.

This element was first discovered in July 2004 by Kosuke Morita

and his group at RIKEN, Japan’s largest multidisciplinary research

institution. After two successful follow-up tests and certificationof the element’s discovery at the end of December 2015, the name2016. This became the first element to be named in the Asian

region, as all the elements identified until then had been found in

fusing two types of nuclei: a thin film of bismuth (209Bi) with atomic

number 83 and mass number 209 was irradiated with a beam of zinc
(70Zn) with atomic number 30 and mass number 70 that had been

accelerated to about 10% of the speed of light. In this experiment,a large linear accelerator (RILAC) with the world’s highest beam

intensity and a gas-filled recoil separator (GARIS), which extracts

only the 113th element from the countless particles produced byirradiation, played a major role. The probability of nuclei fusing is

extremely small, and only three atoms of nihonium were obtained
after 400 trillion collisions. It was also revealed that the lifetime ofnihonium is only 344 microseconds.

E

lements up to the 118th, oganesson (Og), have now beenreported, completing the 7th period of the periodic table.
RILAC

GARIS

©RIKENhe

Akashiworld’s longest bridges. It

crosses the Akashi Strait (orAkashi Kaikyo in Japanese),linking Kobe on the mainland of Honshu with Iwaya on Awaji

Island, and has a total length of 3,911 meters and central span of
1,991 meters. Awaji is then linked with the island of Shikoku by
the Naruto Strait, well-known for the massive Naruto Whirlpools.
Together, these two great bridges provide a seamless route forpeople travelling between the islands of Honshu and Shikoku.

The suspension cables of the Akashi Kaikyo Bridge are supported

by two main towers, which rise 288.3 meters above the sea. The

main cables of the supporting towers consist of 290 strands (wirebundles with regular hexagonal cross sections), each of which is madeof 127 high-tensile galvanized steel wires. Each cable has a diameterof 112.2 centimeters and can support a load of up to 60,000 tonnes.

To protect the wires from wind and rain and to prevent corrosion,
their surfaces are coated with rubber, and the cable interiors areprotected with desalted and dehumidified air, maintaining thestrength and durability of this marvelous suspension bridge.

C©RIKEN

Montenegro
Malaysia

The 53rd IChO 2021 Japan

KaikyoBridge is one of the

Oman

228

5

the longest suspension bridge in the world286

Element#4

Japanese mineral resources

Rhenium

I

ThailandPhilippines

ReS2

1

ELEMENT

QUIZ

Q5

1
2
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4

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Catalyzer 6No.

6Jul. 30

2021

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The 53rd IChO 2021 Japan

Nobel Prize
Research fromJapan 06

M

Development of Palladium-Catalyzed
Cross Coupling Akira Suzuki / Ei-ichi Negishi

any of the functional materials and pharmaceuticals that are

indispensable to modern life are created by organic synthetic

reactions. In order to synthesize such useful materials, carbon–carbon
bond formation reactions are indispensable to link the carbon atomsof organic molecules. A typical example of such a cross-coupling
reaction is the chemical transformation of benzene rings. This reaction

is difficult to achieve by traditional methods using carbocations andcarbanions, but was found to be more easily accomplished by usingtransition-metal catalysts. It is no exaggeration to say that the fieldof cross-coupling reactions
has been led by Japanese
researchers,

and

in

particular, the palladium-catalyzed cross-coupling

reactions of aryl halides

with arylmetal (boron orzinc) reagents developedby Akira Suzuki and Ei-

Photo by Hokkaido University

Dr. Akira Suzuki Dr. Ei-ichi Negishi( 1930- )( 1935-2021 )ichi Negishi in the 1970s are extremely versatile. They have a wide
range of applications, and are currently being used in the synthesisof numerous pharmaceuticals and organic electroluminescentmaterials. In 2010, Akira Suzuki and Ei-ichi Negishi were awarded
the Nobel Prize in Chemistry, together with Richard F. Heck, for the

IChO2021 Problem Q5development of such a truly practical synthetic reaction.

Unsaturated bonds
between heavier main-group elements
In the late 1800s, the periodicity of the properties of elements was
discovered; this concept suggests that elements that exhibit similar
properties appear in a periodic order when arranged according totheir atomic numbers. Ultimately, the stringent application of thisprinciple resulted in the creation of the periodic table of elements by
Mendeleev in 1869. In general, elements in the same group, i.e., thoselocated in the same column in the periodic table, are thus expected to
exhibit similar properties. What do you think about this statement? Is
this true for all the elements in the same group?
Silicon is the heavier homologue closest to carbon in the
periodic table, and the analogies between carbon and silicon
have been discussed controversially for a long time. For example,
while the chemistry of unsaturated compounds of the maingroup elements ofthe second row suchas olefins (R2C=CR2)
is plentiful, that of
the heavier-element
homologues of these
multiple-bond compounds has remained underdeveloped incomparison, which is predominantly due to their extremely highreactivity and inherent instability under ambient conditions. Prior to
the 1970s, all attempts to synthesize compounds with multiple bonds
between heavier main-group elements were unsuccessful, and only
cyclic oligomers or polymers with single covalent bonds between
the main-group elements were obtained. Accordingly, the scientificconsensus at the time was that such heavier main-group elements areprobably not able to form π-bonds (‘double-bond rule’). However,
ambitious chemists were ultimately able to isolate and characterize
several kinds of such compounds with unsaturated bonds between
heavier main-group elements using bulky substituents for stericprotection (‘kinetic stabilization’). For example, the first distannene(R2Sn=SnR2, Lappert 1973), diphosphene (RP=PR, Yoshifuji 1981),
disilene (R2Si=SiR2, West 1981), and disilynes (RSi≡SiR, Wiberg
and Sekiguchi 2004) have been synthesized as stable compounds
by using sterically demanding substituents, which disproved the
double-bond rule. Since then, the unique features of unsaturated
compounds of heavier main-group elements have been investigatedin detail, attracting much attention to the area of main-groupelement chemistry. For example, it has been reported that disilenes(R2Si=SiR2) and disilynes (RSi≡SiR) exhibit pyramidalized andbent geometries, respectively, which stands in sharp contrast to theplanar geometry of ethylene and the linear structure of acetylene.
These different structural features should in turn cause different
reactivity and properties, and thus, the chemistry of unsaturated
silicon compounds can be expected to be characterized byunprecedented functions and chemistry that is different from thatof carbon. Thus, it should be noted here that the structure andchemistry of the second-row elements is considerably different infrom those of the heavier main-group elements, as exemplified by
HOH ≈ 104.5°) vs. H2S (bp: –60 °C;
the case of H2O (bp: 100 °C;
HSH ≈ 92°).

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Chemistry ! It's Japan !

Discovery of Adrenaline
Jokichi Takamine / Keizo UenakaW

hen one feels anxious, excited, or nervous, such as during
important exams, public presentations, cheering on sports

teams, muscle training, or when in love, our blood pressure rises
and our heart rate increases. A hormone called adrenaline issecreted by the adrenal medulla when the sympathetic nervous

system becomes dominant. Adrenaline was the first hormone
to be isolated by scientists, in the year 1900. Jokichi Takamineand Keizo Uenaka (1876–1960) played key roles in this
discovery. They succeeded in obtaining 7 grams of adrenaline

crystals from 9 kilograms of bovine and sheep adrenal tissue by
repeated acid and base extraction. Only

after the first successful isolation did thehormone become commercialized as
adrenaline preparation. Since then, it

has become an indispensable agent

for raising blood pressure in surgery,

ophthalmology, and internal medicine.

Dr. Jokichi Takamine( 1854-1922 )The number of lives adrenaline has

saved to date is testament to theimportance of this achievement forhumanity.

Daibutsuden

6 The world’s largest wooden structureC

onstruction of the Great Buddha of Nara started in the year

745, after Emperor Shomu decided to build a huge statueof Buddha to placate social disturbances in the wake of multiple

coups and rebellions. The Buddha statue was completed in 752.
The current Buddha is approximately 14.7 meters tall, and thecircumferences of the platform, the head, and the palm are 70

meters, 2.6 meters, and 2.6 meters respectively. The head wasrestored in the Edo (Tokugawa) period (1603 to 1868), andmost of the body was restored during the Kamakura period(1185 to 1333), but parts of the original statue still remain. The

amount of copper used for building the Buddha varies slightly,
depending on the historical record, but it is estimated to be(Daibutsuden) is enshrined today is 57.5 meters wide in theof nearby residents, and a medical center was establishedthe world, and was designated by the Japanese government as

500 tons. Mercury used as a solvent in the plating process andarsenic contained in copper are said to have caused poisoning
to treat these patients. The Hall where the Great Buddha

232

The 53rd IChO 2021 Japan

east-west direction, 50.5 meters deep, and 49.1 meters high to
the ridge of the roof. It is the largest wooden frame building in
a National Treasure in 1952.

Element#5

Moldova

Japanese mineral resources

PalladiumP
Crystal Museum

ELEMENT

Cyprus

1

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Q6

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4

2

2

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Catalyzer 7No.

7Jul. 312021

234

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Nobel Prize
Research fromJapan 07O

samu

ShimomuraGreen Fluorescent Protein
Osamu Shimomura

becameinterested

in

how

the

bioluminescent jellyfish Aequorea victoria glows in the dark,

and went to Friday Harbor in the U.S. state of Washington with hisfamily every summer to solve the mystery. They collected as manyas 850,000 jellyfish and investigated the nature of the substancethat made them glow. He isolated the substance in question, a kindof protein called green fluorescent protein (GFP). This protein
undergoes a structural transformation to become a chromophoreand emits fluorescence; specifically, via
cyclization and oxidation of three aminoacid residues, Ser65-Tyr66-Gly67. In thejellyfish body, the calcium-responsive

protein aequorin absorbs light, andthen emits blue fluorescence; in turn,
GFP absorbs this blue light and glows

green. However, GFP can also glow on

its own, so Martin Chalfie and Roger Y.

Photo by Nagasaki University

Dr. Osamu Shimomura( 1928-2018 )Tsien used genetic engineering to develop a method of attaching
GFP to other proteins and making them glow. This tool enabled

the analysis of various biological phenomena in cells to reveal
the subcellular localization of proteins (GFP tags), and advanced

research in a wide range of fields including cell and molecularbiology, developmental biology, and medicine. The 2008 Nobel
Prize in Chemistry was awarded to Osamu Shimomura, Martin

Chalfie, and Roger Y. Tsien for “the discovery and development of
the green fluorescent protein, GFP.” Today, artificial fluorescent

IChO2021 Problem Q6

proteins that glow in a variety of colors are being produced.

Coordination polymers: found in minerals - promisingstorage materials for small molecules
An enormous variety of minerals exist in nature. Most of these areinorganic compounds, while some are known as organic minerals.
For example, there are currently 23 known organic minerals that
contain carboxylic acids such as formic acid, oxalic acid, or acetic
acid. In oxalate minerals, the two carboxylate groups (-COO−) of
oxalic acid are linked to various metal ions by coordination bonds
to form network crystal structures (Fig. 1). Although not an
organic mineral, Prussian blue, which was accidentally discoveredin Germany in the early 17th century and has ever since beenvalued as a blue dye, adopts a crystal structure in which iron
cations and cyanide anions (CN−) are linked by coordination bonds(Fig. 2). Prussian blue was also used in Katsushika Hokusai’s
famous woodblock print “Under the Wave off Kanagawa” (ca. 1831;
Fig. 2). Such crystalline network structures, which arise fromcoordination bonds between metal ions and bridging ligands, arecalled ‘coordination polymers’.
In the middle of the 19th century, in parallel to the developmentof X-ray crystallography, chemists began to synthesize newcoordination polymers using organic ligands that do not necessarily
exist in nature. The crystal structure of an organic ligand-bridged
coordination polymer that consists of adiponitrile and copper ions
was firstly reported by Yoshihiko Saito et al. in 1959 (Fig. 3; left).
We can only wonder how amazed these scientists must have beenat the time by the complexity of the “reticular” networks of thesecrystal structures. After that, various other crystal structures werereported and chemists started to think about useful applications
for these characteristic crystal structures.
In 1997, Susumu Kitagawa of Kyoto University discovered thatthe nanometer-sized small pores formed inside coordination
polymers that consist of cobalt ions and bipyridine could be used
as a gas-storage material (Fig. 3; right). Such “porous coordination
polymers” can store large amounts of gas inside the crystals and are
now being put to practical use. The applications of these materials
can be expected to continue to expand in the future and probableapplications include storing H2 to power fuel cells, capturing CO2
to ameliorate global warming, and storing H2O to water the desert.

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VR TOUR SPring-8

7

Kumano Kodo

Kumano Kodo (literally means the old ways of Kumano) is a

general term for the network of pilgrimage routes that leadto the three main Kumano Shrines: Kumano Hayatama Taisha,
Kumano Hongu Taisha, and Kumano Nachi Taisha. Located in thesouthwestern part of the Kii Peninsula and starting eastwards fromthe city of Tanabe, the network spans Mie, Nara, Wakayama, andOsaka Prefectures. It was registered as a UNESCO World Cultural

Heritage Site in 2004. Kumano is regarded by the Japanese people asa sacred place for mountain worship, a practice that originates fromthe worship of nature in which the gods dwell in rivers, waterfalls,
and huge rocks. The Kumano Kodo is also mentioned in the ancienthistory book Nihon Shoki, written during the Nara period (710 to794). People walking the routes today can see the same scenery as
the pilgrims who visited Kumano to gain enlightenment in the olddays, including such joys of nature as the large cypress trees that are

more than 800 years old, and the smooth cobblestones on the paths.

Other Local Dialects
in the Kansai Region
In Catalyzer No. 0, we presented a list of useful Japanese phrases, and in

Catalyzer No. 1, a comparison of everyday phrases in Standard Japaneseand Kansai-ben, a dialect spoken in the Kansai region. There are several sub-regional dialects too, each with distinctive expressions, spoken in various parts ofKansai. When a Kansai person speaks, we can often tell which part in the region

they come from. The English phrase “Very Good!”, for example, is Totemo Iine! instandard Japanese, Meccha Eeyan! in Osaka; Erai Yoroshiyan! in Kyoto; Erai Eegai!

in Hyogo; Erai Eenaa! in Shiga; Gottsu Eena! in Nara; and Yanikoo Eewaisho! in
Wakayama. Look at some of the other differences in the table below.

Standard
Japanese

Osaka

Hyogo

Kyoto

Shiga

Nara

I agree.

English236

Wakayama

Sou-dane.

Seya-na.

Seya-na.

Soya-na.

Hoya-na.

Seya-na.

Soya-ne.

No, you can't!

Dame-dayo!

Akan-de!

Akkai-ya!

Akan-shi!

Akasen!

Akan-de!

Akanaa!

Lots

TakusanGyousan

Jousan

Tanto

Yokke

Youke

YousanNo problem.

Kamaimasen. Kamahen.

Becchonai.

Dannai.

Dannai.

Kamahin.

Kitsukainai.

I can't.

Dekinai.

Dekehen.

Dekihin.

Yousimahen.

Dekihin.

Dekiyan.

Yousen.

Bottom

Saikai

Dobe

Getta

Bebetako

Gebeccha

BebetaBetta

Do not come

Konai

Kēhen

Kōhen

Kīhin

Kiyahen

KyahenKēhen

The 53rd IChO 2021 Japan

PHOTO SELECTION
from VR Venue

during IChO2021

Bangladesh

TurkeyJapan

A message from the student narratorsof the practical examination video
We are fortunate to be given this opportunity to help theInternational Chemistry Olympics in this way. We are students
who like both English and chemistry. We believed challenging
ourselves to try new things would give us new perspectives,
and we thought taking this opportunity would give us new
discoveries and experiences. Being able to participate in thisevent with friends was another incentive as well.
Although it wasn't an easy task to pronounce the long
names of chemical substances or highly technical chemistryterms properly, we enjoyed dealing with it.
Most of us hope to work in a science field such as medicine,
biology, or space aeronautics. Some of us would like to deal
with environmental problems in the future as well. We are sure
we need to use English to work in this field with the global
scene. We will make good use of this experience that has given
us a chance to
get to knowwhat practicalEnglish is like.
Thank you.

Short short from Editors

The book to take you to
the world of Chemistry
Do you remember what made you fell in love with Chemistry? In

Japan, there are illustrated books that introduce chemistry to children

and fascinates chemists at the same time. Kako is also a scientist
himself and has written many Chemistry stories for children. One ofthem is “Nakayoshi Ijiwaru Genso
no Gakkou.” It means “School of

ELEMENTS with good friends
and mean friends.” This bookintroduces the process of creating

the periodic table by comparing

the properties of elements to thepersonalities of human classmates.

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237

Today's schedule

Element#6

Japanese mineral resources

IndiumI

China

Uruguay

Crystal Museum

We could not takeagroup photo sin
ce theCOVID-19 situ
ation inUruguay would
not allow it.
Even when thesituationis getting betterand thestudents will per
form
the test at the sam
eclassroom, ask
ing themto travel to themain city,
Montevideo, just to takea photo, could
not be thebest choice.

Sri Lanka238

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2

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Catalyzer 8No.

8Aug. 1

2021

F

rom the center to the edge, the entire medal forms the shape of a vortex, giving theimpression of a whirling motion. This movement represents the global impact andupcoming success of young students, originating at IChO2021 Japan. Through the designs
found on both sides of the medal, IChO2021 supports the bright future of the contestants.

The obverse side features three kinds of popular auspicious patterns to express aspects ofJapanese culture.

The reverse side contains the logo, which is represented in a simple and emphatic way

through an image that spreads across the world.

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Nobel Prize
Research fromJapan 08

P

Discovery and Development of
Conductive Polymers Hideki Shirakawa

lastics (polymers) are used in all aspects of our daily living

and enrich our lives with their low cost, light weight, andflexible formability. Initially, plastics were thought not to conduct

electricity and were used as insulators. However, various conductive
polymers have now been developed and boast a wide range ofapplications, including touch panels for smartphones andelectrodes for lithium-ion batteries. The development ofconductive polymers that led to innovation in the world of plastics
was triggered by aserendipitous(unexpected) discovery
by Hideki Shirakawa.

When a student in hislaboratory accidentallyused one thousand times
the required amount of

catalyst to synthesize

polyacetylene, he obtained a shiny, filmlike material that was completely different
from the conventional black powdery
polyacetylene. Although polyacetylene

has many π-electrons, they cannot movefreely, and the film-like polyacetylene did

not show sufficient conductivity in its
original state. However, through trial andPhoto by Kazuhiko Sugano

Dr. Hideki Shirakawa

error, they came up with a method to dope

( 1936– )

carriers that act as electron acceptors, and when they added asmall amount of bromine or iodine, the conductivity surged 10

million times. This discovery led to a dramatic development inresearch on conductive polymers. For this series of achievements
in laying the foundation for the development of conductive

polymers, which became indispensable to modern society, Hideki

Shirakawa was awarded the Nobel Prize in Chemistry in 2000,
together with Alan Jay Heeger and Alan Graham MacDiarmid.

Japan is a “fermentation powerhouse”
J

apan, with its warm and moist climate, is a “fermentation

powerhouse” where microorganisms are very efficacious.

Fermented foods such as soy sauce, natto (fermented soybeans),
and katsuobushi (dried bonito flakes), which are made by growing
mold on fish to remove moisture, are world-famous.

Soy sauce

K

Natto

is

Katsuobushi

local climate. In Wakayama, facing the Pacific Ocean, “Nare-with rice and then lacto-fermented,
servedoccasions.

onNare-zushi

celebratory“Funa-zushi”,

kind of Nare-zushi, is madealong the shoreline of Lakeafor one to three years. The

240

The 53rd IChO 2021 Japan

increases its shelf life. There
are two types of pickles inJapan: those made of lacto-

Suguki-zuke

those made by soaking veges

in koji (rice malt) or sake lees to

add to their flavors. For example,“Suguki-zuke” is a lacto-fermented

Nara-zuke

turnip and “Nara-zuke” is a type of cucumber

or squash pickle that has been pickled in sake lees for years.

Koji and yeast are crucial for making sake and basic seasonings

such as soy sauce, miso, mirin, and vinegar. Jokichi Takamine

devised a method to extract a type of diastase (digestive agent),
named Takadiastase later, during the process of growing koji.

Koji is deeply connected to the history of biochemical research inby marinating spawningfermenting it with ricesourness, and the acidity

who succeeded in crystallizing adrenaline (Catalyzer No. 6),

Biwa. Funa-zushi is madecrucian carp in salt andnovel cheese-like flavor andfermented vegetables, andansai is also home to many fermented foods rooted in thezushi”, salted fish wrapped in plant leaves

lactic fermentation gives it a

Funa-zushi

Japan. Against this background, Aspergillus oryzae, the main bodyof koji that supports Japanese food culture, was designated as
Japan’s national fungus in 2006 by the Brewing Society of Japan.

IChO2021 Participating Teams
Armenia

Belgium

Costa Rica

Australia

BrazilCroatia

Austria

Bulgaria

CyprusAzerbaijan

CanadaCzech Republic

Bangladesh

China

Denmark

Belarus

Chinese Taipei

El Salvador

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241

242

Estonia

Iceland

Kazakhstan

Finland

India

Korea

FranceIndonesia

Kyrgyzstan

Georgia

Iran

LatviaGermany

IrelandLithuania

GreeceIsraelLuxembourg

HungaryJapan

Malaysia

The 53rd IChO 2021 Japan

MexicoNorth Macedonia

Qatar

Moldova

NorwayRomania

Mongolia

Oman

Russian Federation

Montenegro

Pakistan

Saudi Arabia

Netherlands

Philippines

SerbiaNew Zealand

PolandSingapore

Nigeria

Portugal

Slovakia

Catalyzer

243

244

Slovenia

Thailand

United States of America

South Africa

Trinidad and Tobago

Uruguay

Sri Lanka

TurkeyUzbekistan

SwedenTurkmenistan

Venezuela

Switzerland

UkraineVietnam

Syria

United Arab Emirates

Tajikistan

United Kingdom

The 53rd IChO 2021 Japan

Remote IChO2021 Japan

Looking Back Remote IChO2021
I

n the middle of January 2021, the Organizing Committeeof IChO2021 Japan met with the Steering Committee (SC)of the IChO. We discussed two proposals; for an in-person IChO
and a remote IChO. Unfortunately, it was already clear that all theelements of the IChO described above could not be included in an
in-person IChO during the COVID-19 pandemic, due to difficulties
in immigration control and of the need for social distancing.

The 53rd International Chemistry Olympiad (IChO) 2021
Japan was originally planned to follow the 2020 Olympic andParalympic Games in Tokyo, Japan. The interest to chemistry fromthe people was expected to be enhanced when a scientific Olympiad
would be held after the excitement of a sporting Olympiad.

W

hen we heard the first reports of COVID-19 early in 2020,
it appeared to be a minor concern. Despite the virus being

thought of as causing a new kind of cold, we knew that the commonThe first priority of IChO is, of course, the safety of allparticipants. After our meeting with the SC, we finally decided

to hold IChO2021 Japan as a remote event. At the end of February,
when we had a second meeting with SC, the holding of a remote
IChO was approved.

Even in a remote format, all elements essential to the
IChO had to be maintained as much as possible:(1) Examination
The competition involves theoretical problems, and was strictly

cold is inactive in summer, when the IChO was to be held. However,monitored to avoid cheating. However, in order to reinforce theParalympics were postponed, and the 52nd IChO2020 in Turkey

demonstrated. We are delighted if those who are inspired by theshortly after the pandemic spread across the globe, it became evident

that COVID-19 was active in summer, too. The 2020 Olympics andwas held remotely, because the University venue could not be used
for an in-person event in the period of IChO.

The IChO is composed of three key elements:(1) Examination

importance of laboratory work, an activity was developed inwhich the practical tasks prepared for IChO2021 Japan were

demonstration can prepare and submit original videos in which
they attempt the practical tasks and discussions. Reports on thetasks will also be highly welcome.
(2) Communication

We prepared avatars for all participants. Everyone participatedChemistry is an experiment-based science, with every theory

in events and activities via their avatars. We also prepared virtual(2) Communicationsuch virtual venues.

coming out of the laboratory. Therefore, both theoretical andpractical examinations play important roles in the IChO.

Talented students from all over the world come together to takepart in the IChO. Conversation, cooperation, and communication

venues in which avatars can enjoy close conversation, cooperation,and communication with others. Some events also took place in(3) Culture

IChO participants were offered the opportunity for virtual visitswith each other provide a great opportunity for promising

to several locations. As well as those locations that had been

(3) Culture

to hazards, sensitivity, space limitations, or language difficulties.

youngsters to enjoy international experiences and to make friends
with other participants via their common interest, chemistry.

The venue chosen for IChO2021 Japan was the ancient capital ofJapan, where the first government of Japan was established 2681
years ago (according to Japanese legend). Several places were to bevisited, including not only very old temples but also state-of-theart scientific institutes.

planned for the in-person IChO, we have added several that are very
interesting to experience but not suitable for in-person visits due

However, the participants’ avatars can readily visit such restricted

locations. The menu of cultural tours for our remote IChO holds
more interest than would otherwise be possible.

This remote IChO has given us the chance to make the latest

technology to provide great opportunities and special experiences
to all participants.

Catalyzer

245

ChairVice Chairs

Kohei
Tamao

KyoheiTakahashi

Finance Committee

Chair

Chair

Tadao
Kondo

Executive Committee

Chair

Teiji
Koge

Technology Subcommittee

Chair

Vice
Chair

Yasushi
Tsuji

Yoshiaki
Nakao

YoshikiChujo

Nobuhiro
KiharaEvent Subcommittee

Chair

TetsuakiFujihara

Vice
Chair

Yoshiki
Chujo

Kazuo
TanakaVice
Chair

Kunihiko
Yokoi

SeijiroMatsubara

Tadao
Kondo

Teiji
Koge

Science Committee

Vice
Chair

Chair

Hiroshi
Nishihara

Fundraising Committee

Chair

Nobuhiro
KiharaKyoheiTakahashi

Practical Problem
Subcommittee

Chair

Hiroshi
Nishihara

Tetsuzo
Ishikawa

Theoretical Problem
Subcommittee

Chair

Takayoshi
KurodaHideki
Yorimitsu

Keisuke
Asano

Ken-ichiFujitaNobuaki
Kambe

Takamitsu
FukudaHiroshi
Kominami

Tsukasa
MatsuoTakeshi
Hasegawa

Takashi
Hiroi

SatoshiHorikeYasutaka
Kataoka

Tsumoru
Morimoto

Masahiro
Nakagawa

Shin-ichi
Naya

Naoki
Noma

AtsushiSudo

SaburoHosokawa

Yoshiyasu
Matsumoto

Naoya
Nishi

YusakuSuenaga

YoshiroYamagiwa

HiroshiOkuyamaHayate
Saito

Takahiro
Sasamori

Hirofumi
Sato

Jun
Shimokawa

Ryo
Shintani

Takayuki
TanakaKazunori
Tsubaki

SayakaUchidaHiroyasu
Yamaguchi

Venue Subcommittee

Chair

ManabuIshifune

Chair

HisashiFujihara

KentaroOkano

Yoshihiro
Yamaguchi

Public Relations
Subcommittee

MakotoYasudaVice
Chair

YoshitoTobe

Atsunori
Mori

SatoshiTsuchima

Vice
Chair

Yuki
Yamasaki

Vice
Chair

General Affairs
Subcommittee

Chair

AkihitoKonishiMasahiro
Miura

Secretariat
HayanonYoshiyuki
Manabe

246

Akiko
Ikeda

YasushiImada

YutakaNishiyama

FumikoKakoi

Chigusa
Rao

Teruhisa
KanedaYoshiyasu
TanakaThe 53rd IChO 2021 Japan

Kensuke
Kiyokawa

AkihiroTsurusaki

Syozo
KoshinoTakuyaYamakado

SatoshiMinakata

MakotoOuchi

Yasutaka
SumidaTakashiUemuraMasayaSasaki

HiroshiSeta

Junko
KotokuToday's schedule

QUIZ

Q8

2

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8

he Daisenryo Kofun, located in the city of Sakai in Osaka

Prefecture, was built in the early to mid-5th century andis considered to be Japan’s largest kofun (Emperor’s tomb). It is2

1

SiliconDaisenryo Kofun

1
2
3
4

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twoquizzes!!

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Japanese mineral resources

S

1

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4

one of the more than 200 burial mounds that make up the Mozu

Tumulus Group, which were built between the late 4th and early 6th
centuries. The three-tiered, keyhole-shaped tomb is 486 meters inlength and 654 meters at its widest, and is surrounded by a threetiered moat. Although the actual identity of the Emperor buried

there is unknown, the Daisenryo Kofun was recorded as the tomb of3

Emperor Nintoku in a collection of laws compiled by the Imperial
Household Agency in the early 10th century. The Daisenryo Kofun

is one of the three largest tombs in the world, together with thepyramid of King Khufu

in Egypt and the tombof Qin Shi Huang in

China. It was designatedas a UNESCO World
Heritage Site in 2019.

Catalyzer

247

Catalyzer 9No.

9Aug. 22021

Welcome Message from China

We are looking forward to welcoming you from all over theworld to participate in the 54th Chemistry Olympiad in

2022, at Nankai University, in Tianjin city. Tianjin, a meaning ofthe ‘emperor’s docks,’ resides in Northern China, the key junctionbuilding a worldwide academic community and a shared futurefor humankind.

As a chemist, I have found that Chemistry can start from simpleof transportation and communication for China and its connection

concepts and extend to understand the complexities of the world.

As the Vice-Chancellor of Nankai University, it is my greatest

spirit is coincidently shared with the IChO, so we are genuinely

with the world.

pleasure to introduce Nankai University as the 54th IChO host.
Founded in 1919, Nankai University has played a vital role in Chinese

education over the last 100 years. Today, Nankai has grown tothree modern university campuses, plus a full range of educational
institutions. Nankai University is a leading multidisciplinary

and research-oriented state university, consisting of 26 colleges,
covering areas from natural science to humanities, at all levels.

As a member of the Global University Leaders Forum, Nankai

University strives continuously to deepen its internationalizationand globalization process, both in education and research.

Not only does Nankai offer opportunities for students to study
abroad, but it also provides a growing number of well-supported

international studentships and scholar bursary programs eachyear. These broaden our academic horizons and contribute to

248

IChO2022

The 53rd IChO 2021 Japan

Here at Nankai, one is always encouraged to develop social
responsibility, practical capabilities, and a creative spirit. This

looking forward to welcoming the young Olympians to Nankai

University, bringing sparks of inspiration and ideas, scientifictalent, and starting friendships. Right now, we are working as hard
as possible to ensure you will have a safe, and a special IChO in

China. We sincerely hope that the pandemic will be over and theworld will go back to normal quickly.
Finally, we are looking forward towelcoming you to Tianjin, in 2022!

Closing Remarks
by Vice President of IChO2021
IChO2021 JapanT

hank you for kind introduction. My name is Kyohei Takahashi,
and I’m originally from a Japanese chemical company,

and also ex-Chairman of Japan Chemical Industry Association,

an association of all Japanese chemical companies. In Japan,

these virtual tours! We also hope you enjoyed communication withmany new friends from all over the world in the virtual space.

For all of you who gloried as gold, silver, and bronze medal winners,

academic society and industry association jointly continue tocongratulations! Your past effort comes into full bloom now! Also,

Chemistry Olympiad Japan Committee.

an honor you should be proud of. Your experience of this time willcontribute to overall chemical society, and it is my honor to work
as a representative from the chemical industry in this International
The 53rd International Chemistry Olympiad in Japan, or

IChO2021 Japan, will be closed today after the fruitful session of
9 days. Although due to the ongoing COVID-19 pandemic, we had

to have the meetings by WEB system, we had participants from 85
countries and regions. This is the largest number IChO has ever had.

This was made possible by the devoted efforts of the Steering

Committee and Chairman Dr. Gábor Magyarfalvi, all national

contacts of each country and region, and those who conducted

selection of student representatives. I would like to express our
sincere thanks to all of you. In addition, thanks to the grate efforts

of all mentors, science observers, and invigilators, examinations in
all countries and regions were fairly conducted. I really appreciate
your efforts and cooperation.

In the host country Japan, sponsorship was provided for us bymany governmental agencies including Ministry of Education,
Culture, Sports, Science and Technology, Ministry of Economy,

Trade and Industry, Japan Science and Technology Agency, andmore than 180 chemical companies and associated companies.
Here I would like to report that this IChO has been operated under
the partnership of All-Japan. Let me express my heartfelt thanks toall organizations and persons who supported us.

Now all of more than 300 students from all over the world taking

part in IChO2021 Japan, thank you for your on-line participation

despite this difficult situation! Did you demonstrate your ability
and results of your daily efforts to the full? I believe all of you

did! Properly speaking, you should come to Japan, become goodfriends with other students, and directly feel Japanese science,

let me congratulate all other students participated, because taking

part in the IChO as representatives from your country or region islet you gain great self-confidence and support in your future.

Chemistry has infinite potential. The chemical industry is the

only industry which has a name of science in its name, whileother industries, such as the automobile industry and the steel
industry, are called with names of products. This is because thechemical industry is based on chemical technology. Our industry
manufactures various products, and chemistry is utilized in every

possible scene of our life. Therefore, we can say that the chemicalindustry is the blood for all other industries.

Today we are facing global-scale problems such as global

environmental issues, natural resource problems, and energy
problems. These problems may jolt the future of human beings.

As you know, the UN Sustainable Development Summit held in

September 2015 adopted a set of international development goals
called “Sustainable Development Goals” known as SDGs and mostof such 17 goals requires innovations by chemistry. We believe
and hope young people like you, who have rich knowledge andcapability about chemistry, will lead the achievement of suchgoals. My dear students, this time you represented your homecountries. But in the future, you must lead chemistry in the world,
you must work together with other participants in this IChO, andyou must make great contribution to the solution of difficult global
problems. My young friends, please have high aims, and attempt
new challenges!

At the end of my closing address, I wish you great success in yourbright future. Thank you very much and good luck!

technology, society, and culture. However, we could not invite you
to Japan due to the pandemic. Nevertheless, we provided you withmany extraordinary programs and events only an on-line would becapable of. We provided you with virtual-tour of SPring-8, which is

the world’s largest radiation facility, and on-line visit to Buddhist

temples, Himeji Castle, Kyoto, and Osaka. I am sure you enjoyed

Catalyzer

249

Awards and Closing Ceremony# Closing Ceremony# Aug. 2, 2021

# Awards# Top 3 of Gold Medalists # 1st, Shu Yang # 2nd, Zhangyi Huang # 3rd, Xinyu Cai# Congratulations!
# 3 avatars with reflecting winner's faces# Silver# Congratulations!

# Bronze# Congratulations!

# Gold# Congratulations!

# Honorable Mention# Congratulations!

# Commentary on the Examination# Avatars attended# Remote # Virtual venue# Participants communicated using avatars.
# The space is virtual, but your new friendship is real!

# Message# Closing Remarks

Prof. Gábor Magyarfalvi

Chair of the Steering Committee

250

The 53rd IChO 2021 Japan

Kyohei Takahashi

Vice President of IChO2021 Japan Committee

Prof. Hiroshi
Nishihara
Chair of the Science Committee# Welcome IChO2022

Prof. Jun Chen

Chair of Organizing the Committee of IChO2022
Vice-Chancellor of Nankai University

Gold
Shu Yang

China

Cheng Jun Nicholas Goh

Singapore

Zhangyi Huang

China

Nir Cohen

IsraelXinyu Cai

China

Timofey A. Charkin

Russian Federation

Bangsen Zhao

China

Tudor Lile

Romania

Sobirjon AmanovUzbekistan

Adarsh Reddy Madur

India

Mircea Raul Bodrogean

Romania

Mahbod Alian Fini

IranAleksandr E. Trofimov

Russian Federation

Deniz Guner

TurkeyAnh Duy Nguyen

VietnamAndrei S. Tyrin

Russian Federation

Bo-An Chen

Chinese Taipei

Dhananjay Raman

India

Georgii M. Zhomin

Russian Federation

Yitian Zhu

United States of America

Chun-Cheng Ting

Chinese Taipei

Filip Hůlek

Czech Republic

Phuong Duc Nam Pham

VietnamHarry John List

United Kingdom

Qiyang Zhou

United States of America

Anh Le Thao Nguyen

Vietnam

Berkan Tarak

TurkeyMahyar Afshinmehr

IranChen Yizhou

Singapore

Myeongjin Shin

Korea

Alexander Ramsay Thow

United Kingdom

Alexandru Catalin Dianu

Romania

Rui-Xi Wang

Chinese Taipei

Catalyzer

251

SilverDuong Hoang Nguyen

VietnamEhsan Naderi Donig

Iran

Stefan Dimitriu

Romania

Patrik Žnidaršič

Slovenia

Sebnem Gul

TurkeySeoyeon Kim

Korea

Uladzislau Hlatankou

BelarusGerel Bayarmagnai

Mongolia

Alphonsus Yu Xiang Neo

Singapore

Temujin Orkhon

Mongolia

Michal Piotr Lipiec

PolandKien Phuong

United States of America

Oscar Dong

Australia

Tong Wu

Ireland

Seung Jae Kang

Korea

Zachary John McGuire

United Kingdom

Nikhil Seshadri

United States of America

Rishit Singla

India

Faatih Regind Qashash Roman Indonesia

Andy Cai

CanadaBernard Tze Wei Kwee

Singapore

Lita Tantipraphat

ThailandHsuan-Ting Lin

Chinese TaipeiDžonatans Miks Melgalvis

LatviaMahit Rajesh Gadhiwala

India

Yuya Koike

Japan

Seyed Mohammad Hossein Barakati Iran

Mohammad Rashed AlHudaithi Saudi Arabia

Oisín Colm Ó Feinneadha

Ireland

Abdulaziz Abdulrahman AlJuaid Saudi Arabia

Oleksandr Zaporozhets

UkraineMatúš Tomčo

Slovakia

Goktug Gulsoy

TurkeyItamar Steinitz

IsraelShahzod Nazirov

Tajikistan

Gozel Dovranova

Turkmenistan

Hee Seong Yoon

Korea

Ron Angelo A. Gelacio

Philippines

Jirapat Rujirayuk

ThailandSimon Bukovšek

Slovenia

Jovan Marković

SerbiaMichael Schembera

Austria

Linus Albert Schwarz

Germany

Sanzhar Bissenali

Kazakhstan

Muhammad Barotov

Tajikistan

Tim Bastian Enders

Germany

Vinicius da Silveira Lanza Avelar Brazil

Pavel Atanasov Nikolov

Bulgaria

Lucio Saracco

Hungary

Berdigylych Rejepbayev

Turkmenistan

Ioannis Karageorgiou

GreeceDávid Benkő

Hungary

Nichawadee Kanjanakosit

Thailand

Yusup Dovletmyradov

Turkmenistan

Davut Muhammetgulyyev

Turkmenistan

Madiyar Kassymaly

Kazakhstan

Takahiro Takemoto

Japan

Povilas Dapsys

Lithuania

Kohei Nishiura

Japan

Nathan Wayne F. Ariston

Philippines

Bruno Andrzej Skoczen

PolandDaniils Kargins

LatviaKhaidar Kairbek

Kazakhstan

Jakub Krzysztof Kwiatkowski

PolandIhor Kholomieiev

UkraineMohammad Solaiman AlHadlaq Saudi Arabia
Marek Pavlica

252

The 53rd IChO 2021 Japan

Czech RepublicBronze
Kevin Lius Bong

Indonesia

Saeed Sultan Baghdadi

Saudi Arabia

Tadas Danilevicius

Lithuania

Ahmad Thaer Ater

Syria

Khanim Yagublu

Azerbaijan

Maha Ali

Syria

Sathira Jantarakulchai

ThailandJorge García-Ponce

MexicoIrmuun Altankhuyag

Mongolia

Michael Li

CanadaKamil Mambetov

Kyrgyzstan

Lukas Rost

Austria

Neta Eiger

IsraelTeodor Svilenov Maslyankov Bulgaria

István Babcsányi

Hungary

Nadun Naveendra Rajapaksha Sri Lanka

Samuil Vladimirov Petkov

Bulgaria

Yurii Okis

UkraineDurdona Muxtarxujayeva

Uzbekistan

Dimitrije Gligorovski

SerbiaLazar Savić

SerbiaAchira Hansindu Kelambi Arachchige Sri Lanka

Hanif Muhammad ZhafranIndonesia

Marina Malta Nogueira

BrazilDarko Stojchev

North Macedonia

Fran Miletic

Croatia

Vladislavs Tiščenko

LatviaHaruhi IsseJapan

Maciej Swiatek

Austria

Jernej Birk

Slovenia

Keith Wong

Australia

Yangyi Qi

SwedenJohann Sora Blakytny

Germany

Aleksandr Beditski

Estonia

Andrei Banica

CanadaVincent Ng

Australia

Firdavs Sobirov

Uzbekistan

Anas Abbas

Syria

Ketevan Peranidze

Georgia

Adam Szymon Sukiennik

PolandAbdur-Raheem Idowu

NorwayTomáš Heger

Czech Republic

Ruben Tapia

FranceIkromiddin Boymahammadov Uzbekistan

Austin Lin

Australia

Fynn Lasse Noah Kessels

Germany

Patrik Fábrik

Slovakia

Jakub Sochor

Czech Republic

Aigerim Turuspekova

Kazakhstan

Emilio Alonso Venegas-Hernandez Mexico

Nathanael Reza Putra Widjaja Indonesia

Michael Estes

Denmark

Edvards Jānis Treijs

Liis Siigur

Estonia

Georgi Neliyanov Nedyalkov Bulgaria

Jochem van den Broek

Netherlands

Salman Huseynov

Nino Abesadze

Georgia

Cassia Caroline Aguiar da Ponte Brazil

Hayk Aghekyan

Armenia

Angelina Rogatch

Belarus

Aames Juriel B. Morales

Philippines

Benedek Sajósi

Hungary

Théodore Halley

FranceAlina Tumashyk

Belarus

Valerian Mocreac

Moldova

Nariman Shirinli

Azerbaijan

Alexandre Bloquel

FranceLatviaAzerbaijan

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253

Laimis Jurkenas

Lithuania

Hana Gabriela Albuquerque Sousa Brazil

Mahsati Piriyeva

Azerbaijan

Tal Sason

IsraelDaan Roger Stan Vanhaecke Belgium

Tigran Harutyunyan

Armenia

Simonas Melaika

Lithuania

Andrei Kornijenko

Estonia

Sandro Pfammatter

Switzerland

Nevena Stojković

SerbiaIoane Kapanadze

Georgia

Adelina Andrei

Moldova

Fredi Manuel Barraza Hernandez El Salvador

Samuel Kolesár

Slovakia

Tatiana Sviriniuc

Moldova

Sebastian Jacob Krikke

Netherlands

Mason Minghan Liu

New ZealandPaul Johann Dorfer

Austria

Ján Plachý

Slovakia

Lin Bigom-Eriksen

Denmark

Oscar Eric Moran Despard

Ireland

Manujaya Praveen Wijesinghe Sri Lanka

Leonid Asatryan

Armenia

Kiryl Maroz

Belarus

Terry Wang

CanadaMaxim Cojocari-Goncear

Moldova

Honorable Mention

254

Bumchin Dolgormaa

Mongolia

Safwan Sakib

Abhinav Chawla

New Zealand

Gerardo Emiliano Gutierrez-Alvarez Mexico

Aku Hertell

FinlandRafael Dux

Luxembourg

Daria Klymenko

UkraineAoife Mary Morris

IrelandJoão Pedro Bonito CaldeiraPortugalHenri Kärpijoki

FinlandThéo Mignen

FranceDinithi Shalika Madhubhashini Sri Lanka

Ali Marouf

Syria

Daniel Jiyoun Jang

New Zealand

Olga Jerkovic Peric

Croatia

Athanasios Feidakis

GreeceSam Wuji Zhuang

New Zealand

Jean-Marc Furlano

Luxembourg

Samuel Klaver

Finland

Vaidik Rajesh Hurkat

United Arab Emirates

Vid Kavčič

Slovenia

Mahin Kamal Sawdager

Bangladesh

Jessica Rebekka Kurmann

Switzerland

Khalid Hasan Tuhin

Bangladesh

The 53rd IChO 2021 Japan

Bangladesh

Element#8

P

Japanese mineral resources

Antimony

1

1

2

2

Sb2S3

T

his popular word has the meaningof “thank you”. Many people in the

Kansai area say “Ohkini” at the end of

conversation to smooth relations with theperson. Ohkini was originally an adverbthat indicated large quantities. Therefore,“Ohkini Arigato” is the equivalent of“Thank you very much.” Over the years,
this was abbreviated to just “Ohkini.”

Catalyzer

255

IChO 2021 Japan Pre-event

Chemistry! It’s cool!
The 53rd IChO 2021 Japan Public Relations Subcommittee organised three pre-events
to inform junior high and high school students about the IChO and to show them thefun of chemistry.
The first event was held at Kyoto University during Chemistry Week in October
2019, with lectures and hands-on experiments. A large number of junior and seniorhigh school students attended the event, where they heard about the latest research
results and the experiences of the former head of IChO 2021 Japan, and also had theopportunity to try out the precision analysis equipment.
In 2021, due to the pandemic of COVID-19, the events were held online twice, withmore than 300 junior high school students, high school students and members of thegeneral public, including those from overseas.
These students must have thought that “chemistry is cool”, “chemistry is fun” and “I
will challenge the International Chemistry Olympiad”.

256

The 53rd IChO 2021 Japan

IChO 2021 Japan Pre-event
Pre-event Lectures

第 53 回 国際化学オリンピック日本大会 2021
国際化学オリンピックプレイベント 講演会

Event planner and Facilitator
Akihito Konishi

事前申込制

化学との出会いOsaka Univ.

10/19/2019
Atsushi Wakamiya

Kyoto Univ.

Hayate Saito

Kyoto Univ.

Takuya Yamakado

Kyoto Univ.

Kohei Tamao

IChO 2021 Japan Committee

未来を拓く君たちへ
日程

2021年3月13日 土 13：00～15：40

対象

中学生・高校生・一般
申込先
国際化学オリンピック日本委員会ホームページ

https://www.icho2021.org
下記 QR コードからも、お申込できます。

SHIMADZU CORPORATION
玉尾皓平

JEOL Ltd.

参加無料
オンライン開催

申込締切：定員になり次第
プログラム

HORIBA, Ltd.

13:00 開会の挨拶

中條善樹（国際化学オリンピック日本大会実行委員長）

13:05 基調講演

KOMYO RIKAGAKU KOGYO K.K.

「一家に 1 枚周期表」から楽しく学ぶわが国の化学技術の底力
玉尾皓平

深澤愛子

（国際化学オリンピック日本委員会理事長・組織委員会委員長・公益財団法人 豊田理化学研究所所長）

13:55 研究講演１

オリジナル分子をデザインし、創り、光・電子機能を拓く
深澤愛子（京都大学 高等研究院 物質−細胞統合システム拠点（iCeMS）教授）

Toyota Physical and Chemical Research Institute14:25 国際化学オリンピック元日本代表経験談

正田浩一朗さん（東京大学 修士課程 2 年）
森田峻平さん（カリフォルニア大学バークレー校 博士課程 2 年）
浦谷浩輝さん（早稲田大学 博士課程 3 年）

15:05 研究講演 2

化学で未来の医療を変える！

松﨑典弥（大阪大学 大学院工学研究科 教授）

3/13/2021

15:35 閉会の挨拶
松﨑典弥

Hiroki Uratani

Waseda Univ.

Shunpei Morita

U.C. Berkeley

Koichiro Masada

UTokyoMichiya Matsusaki

Osaka Univ.

Aiko Fukazawa

Kyoto Univ.

Kohei Tamao

IChO 2021 Japan Committee

Yoshiki Chujo

IChO 2021 Japan Committee

Yoshito Tobe

IChO 2021 Japan Committee

戸部義人（国際化学オリンピック日本大会広報委員長）

問合せ

国際化学オリンピック日本委員会
担 当：古徳、瀬田
mail：info@icho2021.org

主催：国際化学オリンピック日本大会実行委員会／共催：日本化学会・日本分析機器工業会

第 53 回 国際化学オリンピック日本大会 2021
国際化学オリンピックプレイベント 講演会

Par

化学との出会いt2

未来を拓く君たちへ
日程

2021年7月10 日 土 13：00～15：50

対象

中学生・高校生・一般

7/10/2021

申込先

Makoto Yamashita

Nagoya Univ.

Aya Eizawa

Air Liquide Laboratories

Kenichi Endo

Kyoto Univ.

Shinsuke Sando

UTokyoAoi Takeuchi

UTokyoYoshiki Chujo

IChO 2021 Japan Committee

Yoshito Tobe

IChO 2021 Japan Committee

Japan Analytical Instruments Manufacturers’ Association

国際化学オリンピック日本委員会ホームページ

https://www.icho2021.org/jp/
下記 QR コードからも、お申込できます。

中條善樹

申込締切：定員になり次第プログラム
13:00 開会の挨拶・基調講演

化学で未来を元気に Chemistry! It's Cool!

中條善樹（国際化学オリンピック日本大会実行委員長／京都大学 名誉教授）

13:50 研究講演１

新奇な結合から究極の触媒まで：分子は「設計」できる！

山下

誠

山下

誠（名古屋大学 大学院工学研究科 教授）

14:20 国際化学オリンピック元日本代表経験談

永澤 彩さん（株式会社エア・リキード・ラボラトリーズ 研究員）
遠藤健一さん（京都大学 博士研究員）
竹内 碧さん（東京大学 修士課程 2 年）

参加費無料
オンライン開催
事前申込制

15:00 分析機器の紹介

日本分析機器工業会

15:20 研究講演 2

ケミカルバイオロジー：
分子デザインが実現する創薬山東信介（東京大学 大学院工学系研究科 教授）

15:50 閉会の挨拶
山東信介

戸部義人

（国際化学オリンピック日本大会広報委員長／大阪大学 名誉教授）

問合せ

国際化学オリンピック日本委員会
担 当：古徳、瀬田
mail：info@icho2021.org

主催：国際化学オリンピック日本大会実行委員会／共催：日本化学会・日本分析機器工業会

257

Committee

IChO 2021 Japan Committee
President of IChO 2021 Japan Committee

Vice President of IChO 2021 Japan Committee

Kohei Tamao

RIKEN, TOYOTA Physical & Chemical
Research Institute, Kyoto Univ.

Kyohei Takahashi
Showa Denko K.K.

Boad Members of IChO 2021 Japan Committee

Yoshiki Chujo

Tadao Kondo

Hiroshi Nishihara

Teiji Koge

Kyoto Univ.

UTokyoKenji Fujiyoshi

Mitsui Chemicals, Inc.

SEKISUI CHEMICAL CO., LTD.

Hisashi Yamamoto
Chubu Univ.

Maki Kawai

Kuniaki Tatsuta

Masaya Sasaki

Hiroshi Seta

Institute for Molecular Science

Secretariat of IChO 2021 Japan
Committee

258

NIPPON SHOKUBAI CO., LTD.

The 53rd IChO 2021 Japan

Waseda Univ.

Secretariat of IChO 2021 Japan
Committee

Committee

Special Advisor
Former President of the Chemical Society of Japan :Fujishima, Iwasawa, Kobayashi, Murai, Nakanishi, Noyori, Sakakibara,
Former Chairman of Keidanren, Japan Business Federation : Sakakibara, Yonekura(Alphabetical order)

Akira Fujishima

UTokyo,Tokyo University of Science

Yoshimitsu Kobayashi

Mitsubishi Chemical Holdings
Corporation

Yasuhiro Iwasawa

UTokyo,The University ofElectro-Communications

Shinji Murai

Osaka Univ.,
Nara Institute of Science andTechnology

Ryoji Noyori
Hiroyuki Nakanishi

Mitsui Chemicals, Inc.

Sadayuki Sakakibara
Toray Industries, Inc.

President of the 42nd IChO 2010
Japan,
Nagoya Univ.,
Japan Science & Technology
AgencyHiromasa Yonekura

SUMITOMO CHEMICAL COMPANY,
LIMITEDThe 53rd IChO 2021 Japan Organizing Committee
Chair of the 53rd IChO 2021 Japan Organizing Committee
Kohei Tamao

RIKEN, TOYOTA Physical & Chemical Research Institute, Kyoto Univ.

Vice Chairs of the 53rd IChO 2021 Japan Organizing Committee
Kyohei Takahashi

Showa Denko K.K.

Teiji Koge

SEKISUI CHEMICAL CO., LTD.

Yoshiki Chujo

Kyoto Univ.

Hiroshi Nishihara

UTokyoTadao Kondo

NIPPON SHOKUBAI CO., LTD.

259

Committee

Members of the 53rd IChO 2021 Japan Organizing Committee(Members at inception: December 6, 2017)
Hitoshi Shiozaki

Kindai Univ.

Yoshihiko Hosoi

Kindai Univ.

Taro Eguchi

Kinka Chemical Society

Osamu Ishitobi

Japan Chemical Industry Association

Masanori Ikeda

Kansai Chemical Industry Association

Hiroaki Ishizuka

Japan Association for Chemical Innovation

Hisashi Yamamoto

The Chemical Society of Japan

Taketsugu Fujiwara

The Society of Chemical Engineers, Japan

Yoshiki Chujo

The Society of Polymer Science, Japan

Koichi Eguchi

Catalysis Society of Japan

Kenichi Udagawa

The Electrochemical Society of Japan

Jun Muto

The Japan Petroleum InstituteNaoto Oku

The Pharmaceutical Society of Japan

Ryuichiro Sato

The Japan Society for Bioscience, Biotechnology, and Agrochemistry

Tetsuo Okada

The Japan Society for Analytical Chemistry

Yutaka Kunigo

The Japan Institute of Energy

Kazuyuki Hirao

The Ceramic Society of Japan

Junichi Yoshida

The Society of Synthetic Organic Chemistry, Japan

Yasuhiro Iwasawa

Japan Union of Chemical Science and Technology

Haruo Hosoya

Society of Computer Chemistry, Japan.

Nobuhiro Kihara

The Steering Committee

Masaya Sasaki

The 53rd IChO 2021 Japan Committee

Observer members of the 53rd IChO 2021 Japan Organizing Committee(Members at inception: December 6, 2017)
Hiroki Matsuo

Ministry of Education, Culture, Sports, Science and Technology

Akihiro Tada

Ministry of Economy, Trade and Industry

Masako Kato

Science Council of Japan

Masato Masaki

Japan Science & Technology Agency

Kazuki Okimura

The Japan Foundation of Public Communication on Science and Technology

Nobuyuki Miyamoto

Japan Society of Physics and Chemistry Education

Yasuo Yamatani

Japan Junior High Schools Science Education Society

Shuji Hosoda

Japan Broadcasting Corporation

Tomohiro Murayama

The Asahi Shimbun Company

Isao Ishida

The Asahi Shimbun Company

Yukiko Motomura

The Mainichi Newspapers Co.,Ltd.

Kyoko Takita

The Yomiuri Shimbun

Toshihiko Yano

Nikkei Inc.

Koichiro Takahashi

K.K.Kyodo News

Osamu Odajima

The Chemical Daily Co.,Ltd.

Keizo Takeuchi

The Science News Ltd.

260

The 53rd IChO 2021 Japan

Committee

Fundraising Committee
Chair of Fundraising Committee

Chair of Fundraising Subcommittee

Kyohei Takahashi

Tetsuzo Ishikawa

Showa Denko K.K.

Showa Denko K.K.

Company

Fundraising
Committee

Fundraising
Subcommittee

AGC Inc.

Yoshinori Hirai

Tsuguhide Isemura

Asahi Kasei Corp.

Nobuyuki Kakizawa

Shusaku Shidahara

Daicel Corporation

Akihisa Takabe

Fusayoshi Matsuyama

Denka Company Limited

Kenji Nakano

Kiyoshi Asami

DIC Corporation

Kazunari Sakai

Masanori Fujimaki

ENEOS Corporation

Tsutomu Iwasaki

Kato Hideyasu

FUJIFILM Corporation

Naoto Yanagihara

Michihiro Shibata

Idemitsu Kosan Co.,Ltd.

Kazuo Maruyama

Motoki Yamada

JSR Corporation

Shuichi Sugawara

Yuichi Eriyama

KANEKA CORPORATION

Akira Iwazawa

Naoki Furukawa

Kao Corporation

Hideaki Kubo

Kouji Maeda

Mitsubishi Chemical Holdings Corporation

Ken Fujiwara

Keiji Matsumoto

MITSUBISHI GAS CHEMICAL COMPANY,INC.

Masamichi Mizukami

Yoshikazu Shima

Mitsui Chemicals, Inc.

Masaharu Kubo

Akihiko Matsunaga

Nippon Kayaku Co., Ltd.

Yukio Tachibana

Yoshimi Inoue

NIPPON SHOKUBAI CO.,LTD.

Kinya Nagasuna

Teruhisa WadaNIPPON STEEL Chemical & Material Co., Ltd.

Satoshi Iijima

Hideo Ishii

Nissan Chemical Corporation

Katsuaki Miyaji

Hisayuki Watanabe

NOF CORPORATION

Toshiyuki Hayashi

Hajime Kusumi

SEKISUI CHEMICAL CO.,LTD.

Hiroyuki Taketomo

Koji Onishi

Shin-Etsu Chemical Co.,Ltd.

Hiroaki Okamoto

Naoto Tate

Showa Denko Materials Co., Ltd.

Mitsuyoshi Toyoshima

Chie Noumi

Sumitomo Bakelite Co., Ltd.

Masayuki Inagaki

Hiroshi Aiba

SUMITOMO CHEMICAL COMPANY, LIMITED

Hiroshi Niinuma

Takashi Hatayama

TEIJIN LIMITED

Shigeo Ohyagi

Masaru Shiraha

TOAGOSEI CO.,LTD.

Susumu Miho

Naohito Hayashi

Tokuyama Corporation

Fumiaki Iwasaki

Hiroyuki Kato

Toray Industries, Inc.

Hideki Hirabayashi

Takumi Aoki

Tosoh Corporation

Keiichiro Nishizawa

Motohiro Oguri

Ube Industries, Ltd.

Hideo Tamada

Osamu Akutagawa

Zeon Corporation

Makoto Yokota

Teruhiko Suzuki

261

Committee

Finance Committee
Chair of Finance Committee

Chair of Finance Committee

Tadao Kondo

Teiji Koge

NIPPON SHOKUBAI CO., LTD.

SEKISUI CHEMICAL CO., LTD.

Kansai Chemical Industry Association

Yasushi Aoki

Kinka Chemical Society

Masami Takahashi

Osaka Univ.

Satoshi Minakata

SHIMADZU CORPORATION

Satoshi Moriyasu

Showa Denko K.K.

Tetsuzo Ishikawa

262

The 53rd IChO 2021 Japan

Hiroyuki Niiuchi

Hideki Tominaga

Takahide Saidera

Hiroto Itoi

Committee

Science Committee
Chair of Science Committee

Vice Chair of Science Committee

Hiroshi Nishihara
UTokyoNobuhiro Kihara
Kanagawa Univ.

Science Committee Theoretical Problem Subcommittee
Chair of Theoretical Problem Subcommittee

Hideki Yorimitsu
Kyoto Univ.

Members of Theoretical Problem Subcommittee

Takeshi Hasegawa

Takashi Hiroi

Satoshi Horike

Saburo Hosokawa

Kyoto Univ.

Kyoto Univ.

Yoshiyasu Matsumoto

TOYOTA Physical & Chemical ResearchInstitute

UTokyoKyoto Univ.

Naoya Nishi
Kyoto Univ.

Hiroshi Okuyama

Hayate Saito

Takahiro Sasamori

Hirofumi Sato

Kyoto Univ.

Nagoya City Univ.

Kyoto Univ.

Kyoto Univ.

263

Committee

Jun Shimokawa

Ryo Shintani

Takayuki Tanaka

Kazunori Tsubaki

Sayaka Uchida

Hiroyasu Yamaguchi

Kyoto Univ.

Kyoto Univ.

UTokyoOsaka Univ.

Kyoto Prefectural Univ.

Osaka Univ.

Science Committee Practical Problem Subcommittee
Chair of Practical Problem Subcommittee

Takayoshi Kuroda
Kindai Univ.

Members of Practical Problem Subcommittee

Takamitsu Fukuda

Hiroshi Kominami

Tsukasa Matsuo

Shinichi Naya

Naoki Noma

Atsushi Sudo

Yusaku Suenaga

Yoshiro Yamagiwa

Osaka Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

264

The 53rd IChO 2021 Japan

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Committee

Executive Committee
Chair of Executive Committee

Vice Chair of Executive Committee

Yoshiki Chujo
Kyoto Univ.

Nobuhiro Kihara
Kanagawa Univ.

Executive Committee Venue Subcommittee
Chair of Venue Subcommittee

Hisashi Fujihara
Kindai Univ.

Members of Venue Subcommittee

Manabu Ishifune
Kindai Univ.

Yoshihiro Yamaguchi
Kindai Univ.

Makoto Yasuda
Osaka Univ.

Executive Committee General Affairs Subcommittee
Chair of General Affairs Subcommittee

Masahiro Miura
Osaka Univ.

Members of General Affairs Subcommittee

Satoshi Minakata
Osaka Univ.

Makoto Ouchi
Kyoto Univ.

265

Committee

Yasutaka Sumida

Takashi Uemura

NIPPON SHOKUBAI CO., LTD.

UTokyoExecutive Committee Technology Subcommittee
Chair of Technology Subcommittee

Vice Chair of Technology Subcommittee

Yasushi Tsuji

Tetsuaki Fujihara

Kyoto Univ.

Kyoto Univ.

Members of Technology Subcommittee

Yoshiaki Nakao

Kazuo Tanaka

Kyoto Univ.

Kyoto Univ.

Executive Committee Event Subcommittee
Chair of Event Subcommittee

Kunihiko Yokoi

Osaka Kyoiku Univ.

Vice Chair of Event Subcommittee

Seijiro Matsubara
Kyoto Univ.

Members of Event Subcommittee

Keisuke Asano

Kenichi Fujita

Nobuaki Kambe

Yasutaka Kataoka

Kyoto Univ.

Osaka Univ.

Tsumoru Morimoto

Nara Institute of Science andTechnology

266

The 53rd IChO 2021 Japan

Kyoto Univ.

Nara Women’s Univ.

Masahiro Nakagawa

Kyoto Prefectural OHKI High School

Committee

Kentaro Okano
Kobe Univ.

Satoshi Tsuchima

Tezukayama Junior & Senior High School

Executive Committee Public relations Subcommittee
Chair of Public relations Subcommittee

Yoshito Tobe
Osaka Univ.

Vice Chairs of Public relations Subcommittee

Akihito Konishi
Osaka Univ.

Atsunori Mori
Kobe Univ.

Yuki Yamasaki
Hosei Univ.

Members of Public relations Subcommittee

Akiko Ikeda

Yasushi Imada

Fumiko Kakoi

Teruhisa Kaneda

Sci-Tech Communications Inc.

Kagaku-Dojin Publishing Company,INC.

Kensuke Kiyokawa
Osaka Univ.

Tokushima Univ.

Osaka Prefectural Sumiyoshi High School

Syozo Koshino

St. Michael's Senior High School
Affiliated to Kobe International Univ.

267

Committee

Yoshiyuki Manabe
Osaka Univ.

Yoshiyasu Tanaka

Tokyo Metropolitan Tama High School of
Science and Technology

Yutaka Nishiyama
Kansai Univ.

Akihiro Tsurusaki

Osaka Prefecture Univ.

Takuya Yamakado
Kyoto Univ.

Secretariat
Masaya Sasaki

Secretariat of IChO 2021 Japan
Committee

Junko Kotoku

Secretariat of IChO 2021 Japan
Committee

268

The 53rd IChO 2021 Japan

Hiroshi Seta

Secretariat of IChO 2021 Japan
Committee

Committee

Support Members
Science Committee Theoretical Problem Subcommittee
Yohei Hattori

Rinako Hayashi

Shota Hira

Takanao Ishii

Kyohei Kanomata

Taichi Nishiguchi

Takumi Nishino

Ryota Shibuya

Aoi Takeuchi

Naru Tanaka

Kohei Yoshimura

Ryukoku Univ.

Osaka Univ.

UTokyoKyoto Univ.

Kyoto Univ.

Ricoh Company,Ltd.

Kyoto Univ.

UTokyoUTokyoUTokyoUTokyoScience Committee Practical Problem Subcommittee
Takuma Fukumoto

Kaito Hayakawa

Yukihiro Hazama

Tomoya Higashibayashi

Koki Ijima

Haruki Inoue

Hiroyuki Ito

Yusuke Kano

Naoto Kasahara

Tsubasa Kawakita

Momoka Kiriyama

Takamasa Kishi

Maho Kitahara

Huto Koizumi

Tomoya Kojima

Sora Kosaka

Koyo Kumita

Takeshi Kunimoto

Kota Kurokawa

Taiki Matsuba

Yuki Matsuda

Takuto Mibu

Kamui Mine

Keisuke Miyamae

Ryo Morimoto

Yoko Morita

Natsuki Motobayashi

Yuta Nakagawa

Takumi Nohira

Haruka Ochi

Tomohiro Ohbayashi

Misaki Ohkita

Koji Okuno

Mako Okuno

Sora Sakura

Ryosuke Sasaki

Takuya Shimada

Makiko Shimizu

Shunsuke Suga

Nana TagashiraAkihiro Tsumura

Chisato Wakayama

Shogo Yagura

Tomoki Yamasaki

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Kindai Univ.

Hiroshi Yoshida
Kindai Univ.

269

Committee
Executive Committee Technology Subcommittee
Daisuke Iizuka

Momoe Ishimura

Haru Kitaoka

Kohei Kosaka

Kenta Kuroishi

Naoki Matsushita

Kotaro Nagase

Masashi Nakamura

Junki Ochi

Masaki Ohata

Yuki Sakai

Seiya Sakuragi

Rin Seki

Riko Shimada

Yuto Shimazaki

Hiromasa Takahashi

Toru Taniguchi

Kazuya Tanimura

Tomoaki Yagi

Natsumi Yamada

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Kyoto Univ.

Executive Committee Event Subcommittee
Eri Hudo

Kindai Univ.

Masari Takahashi
Kindai Univ.

Hiyori Takebe
Kyoto Univ.

Executive Committee Public relations Subcommittee
koki Horii

Shizuka ImaiHaruna Iwasa

Jaeyoung Jeong

Kazuki Kido

Miki Saikai

Shota Sasaya

Naoki Sugihara

Daiki Tanaka

Yutaro Wakai

Takuya Yamakado

Yuto Yasumura

Osaka Univ.

Osaka Univ.

Osaka Univ.

Osaka Univ.

Osaka Univ.

Kyoto Univ.

Tetsuji Yata
Osaka Univ.

270

The 53rd IChO 2021 Japan

Osaka Univ.

Osaka Univ.

Kyoto Univ.

Kyoto Univ.

Osaka Univ.

Kyoto Univ.

Acknowledgments to Donations
Company† Alphabetical Order

Idemitsu Kosan Co.,Ltd.
Idemitsu Unitech Co.,Ltd.

A&T Corporation

Inabata & Co., Ltd.

ADEKA Corporation

ISE CHEMICALS CORPORATIONAGC Inc.

ITOCHU Corporation

ARAKAWA CHEMICAL INDUSTRIES, LTD.

Japan Chemical Industry Association

ARONKASEI CO., LTD.

Japan Composite Co., LTD.

Asahi Kasei Corp.

Japan Oil Transportation Co., Ltd.

ASAHI YUKIZAI CORPORATION

Japan U-pica.co.ltd.

ASTOM Corporation

JAPAN VAM & POVAL CO., LTD.

Azuma Co., Ltd.

JSP Corporation

Chugoku Ready Mixed Concrete Co., Ltd.

JSR Corporation

Daicel Corporation

JUNSEI CHEMICAL CO.,LTD.

DAIHACHI CHEMICAL INDUSTRY CO.,LTD.

Kagawa Tokuyama Co., Ltd.

Dainichiseika Color & Chemicals Mfg. Co., Ltd.

KANEKA CORPORATION

Dai Nippon Toryo Company,Limited

KANEKA TECHNO RESEARCH CORPORATION

Denka Company Limited

Kansai Catalyst Co., Ltd.

Denka Consultant & Engineering Co., Ltd.

Kansai Chemical Engineering Co., Ltd.

DENKA POLYMER KABUSHIKI KAISHA

Kansai Chemical Industry Association

DENKA SEIKEN Co., Ltd.

Kansai Tokuyama Trading CO.,LTD.

DIC Graphics Corporation

Kao Corporation

DOW-MITSUI POLYCHEMICALS CO.,LTD.

KOEI CHEMICAL COMPANY, LIMITEDDU PONT-TORAY CO., LTD.

Kuraray Co., Ltd.

ENEOS Corporation

KUREHA CORPORATION

Fukuda Metal Foil & Powder Co., Ltd.

Kyoeisha Chemical Co.,Ltd.

Fuyo Perlite Co., Ltd.

Kyowa Industrial Co., Ltd.

GODO SHIGEN CO.,LTD.

Lion Corporation

Harima Chemicals Group, Inc.

Marubeni Corporation

Hinode Kagaku Kogyo Kaisha. Ltd.

Marubishi Oil Chemical Co., Ltd.

Hoansha Foundation

MARUZEN PETROCHEMICAL CO.,LTD.

Honshu Chemical Industry Co., Ltd.

Matsugaki Chemical Industries, Co., Ltd.

IDEMITSU FINE COMPOSITES CO.,LTD.

Meiwa Plastic Industries, Ltd.
271

Acknowledgments to Donations
MGC AGELESS Co.,Ltd.

ORIENT CHEMICAL INDUSTRIES CO., LTD.

MGC ELECTROTECHNO CO., LTD.

OSAKA ORGANIC CHEMICAL INDUSTRY LTD.

MGC Filsheet Co., Ltd.

OSAKA SODA CO., LTD.

Mitsubishi Chemical Holdings Corporation

Polatechno Co., Ltd.

Mitsubishi Corporation

Prime Polymer Co., Ltd.

Mitsubishi Engineering-Plastics Corporation

PS Japan Corporation

MITSUBISHI GAS CHEMICAL COMPANY, INC.

SAKAI CHEMICAL INDUSTRY CO.,LTD.

MITSUI & CO., LTD.

Sakamoto Yakuhin Kogyo Co., Ltd.

Mitsui Chemical Analysis & Consulting Service, Inc.

SANBO CHEMICAL IND. CO., LTD.

Mitsui Chemicals & SKC Polyurethanes Inc.

Sanyo Chemical Industries, Ltd.

Mitsui Chemicals Agro, Inc.

SDAT Co., Ltd.

Mitsui Chemicals, Inc.

Seibu Tokuyama Ready Mixed Concrete Co., Ltd.

Mitsui Chemicals Industrial Products , Ltd.

SEKISUI CHEMICAL CO., LTD.

Mitsui Chemicals Sun Alloys Co., Ltd.

Sekisui Jushi Corporation

Mitsui Chemicals Tohcello, Inc.

Sekisui Kasei Co., Ltd.

Mitsui Fine Chemicals,Inc.

SHINDAI-ICHI VINYL CORPORATIONMITSUWA FRONTECH CORP.

Shin-Etsu Chemical Co., Ltd.

MORITA CHEMICAL INDUSTRIES CO., LTD.

Shin-Etsu Engineering Co.,Ltd.

MT AquaPolymer,Inc.

Shin-Etsu Handotai Co.,Ltd.

NAGASE & CO., LTD.

Shin-Etsu Polymer Co., Ltd.

Niigata Showa K.K.

Shin-Etsu Quartz Products Co., Ltd.

NIPPOH CHEMICALS CO., LTD.

SHIPRO KASEI KAISHA, LTD.

Nippon Aluminum Alkyls, Ltd.

SHOKO CO., LTD.

Nippon Kayaku Co., Ltd.

Showa Aluminum Can Corp.

NIPPON NYUKAZAI CO., LTD.

Showa Denko Ceramics Co., Ltd.

Nippon Paint Holdings Co., Ltd.

SHOWA DENKO GAS PRODUCTS CO.LTD.

NIPPON SHOKUBAI CO., LTD.

Showa Denko Kenso Co., Ltd.

NIPPON STEEL Chemical & Material Co., Ltd.

Showa Denko Kenzai K.K.

Nissan Chemical Corporation

Showa Denko K.K.

Nissin Chemical Industry Co., Ltd.

Showa Denko Materials Co., Ltd.

NOF CORPORATION

Showa Denko packaging Co., Ltd.

ORGANO CORPORATION

Showa Fine Ceramics Co., Ltd.

272

The 53rd IChO 2021 Japan

Acknowledgments to Donations
Shunan Swimming Club Co., Ltd.

Toray Research Center, Inc.

SHUNAN SYSTEM SANGYO CO.,LTD.

Tosoh Corporation

Sumika Chemical Analysis Service, Ltd.

Toyomi Co., Ltd.

Sumitomo Bakelite Co., Ltd.

Toyota Tsusho Corporation

SUMITOMO CHEMICAL COMPANY, LIMITED

Toyotsu Chemiplas Corporation

Sumitomo Seika Chemicals Company, Limited.

Tsurusaki Kyodo Power Co., Ltd.

SunAllomer Ltd.

UBE EXSYMO CO., LTD.

Sun Arrow Kasei Co., Ltd.

UBE FILM, LTD.

Sun Medical Company, Ltd.

Ube Industries, Ltd.

SUN・TOX CO.,LTD.

Ube Logistics Service, Ltd.

TAIYO HOLDINGS CO., LTD.

Ube Material Industries, Ltd.

Taki Chemical Co., Ltd.

UBE-MC Hydrogen Peroxide Limited

Taoka Chemical Co., Ltd.

UBE Scientific Analysis Laboratory, Inc.

TEIJIN LIMITEDUNION SHOWA K.K.

TOAGOSEI CO., LTD.

West Japan Resicoat Co.,Ltd.

TOHO EARTHTECH,INC.

Yamaguchi Liquid Hydrogen. Corp.

Tokushin Co., Ltd.

YAMAKI CO., LTD.

Tokushou Co., Ltd.

Yamamoto Chemicals,Inc.

Tokuyama Corporation

Zeon Corporation

Tokuyama Dental Corporation
TOKUYAMA-DOWA Power Material Co., Ltd.
Tokuyama Information Service Corporation
TOKUYAMA KAIRIKU UNSO K.K
TOKUYAMA METEL CORPORATION
TokuyamaMTech Corp.
TOKUYAMA SODA TRADING CO.,LTD.
Tokuyama Tsusho Trading Co., Ltd.
Tokyo Liquefied Oxygen Co., Ltd.
TOKYOTOKUYAMA CONCRETE CO., LTD.
Tomitec Co., Ltd.
Toray Fine Chemicals Co., Ltd.
Toray Industries, Inc.
273

Acknowledgments to Donations
Individuals† Alphabetical Order

Kazuhiro Miyamoto
Tsumoru Morimoto

Noriko Chikaraishi

Masanao Morita

Tomoko Hashiura

Yasutaka Nagai

Shigeki Hiramatsu

Masahiro Nakagawa

Haruko Hiroe

Yoshio Nakamura

Masakazu Hirotsu

Shoko Nakazono

Hisao Hori

Tetsuo Nishide

Yuki Hyodo

Yuko Nishimoto

Kimiko Inoue

Suehiro Nitta

Masato Ito

Takeshi Ogawa

Yu ItoTetsuya Ogawa

Ryo Izumi

Kouichi Ohe

Yoshio Kabe

Makoto Ouchi

Toshifumi Kanishi

Manabu Seta

Yasutaka Kataoka

Yutaka Seta

Akio Kawai

Ayako Shibuya

Tatsuya Kawamoto

Ryuichi Shoji

Nobuhiro Kihara

Hiroaki Suga

Ai Kikuchihara

Kentaro Suzuki

Kishiko Koganezawa

Takaya Takei

Mikiko Kosaka

Kei Takeuchi

Jun Koyasu

Yoshiyasu Tanaka

Tetsuo Kozasa

Hiroshi Toho

Yuki Lee

Hayato Tsuji

Junko Makino

Takashi Uemura

Tadashi Makino

Nobuko Watanabe

Seijiro Matsubara

Kayoko Yamamoto

Toshiaki Matsubara

Katsunori Yamanishi

Satoshi Minakata

Kunihiko Yokoi

Masahiro Miura

Hiroshi Yokoyama

Keiko Miyagawa

Kuniyuki Yoshino274

The 53rd IChO 2021 Japan

Special Thanks to Various Contributions
Japan Science and Technology Agency (JST)Ministry of Education, Culture, Sports, Science and Technology (MEXT)
Ministry of Economy, Trade and Industry (METI)
Osaka Prefecture Board of Education
American Chemical Society (ACS)International Union of Pure and Applied Chemistry (IUPAC)
Chemical Society Located in Taipei (CSLT)

Kindai University
We’d like to extend our sincere gratitude to Kindai University, where the 53rd IChO 2021 Japan was originallyscheduled to take place, for their concerted effort to prepare the venue and other hosting arrangements to
conduct theoretical and practical examinations, as well as the cooperation they offered us even after the IChO
2021 was decided to be held remotely, including the provision of the laboratory as an experimental demonstration
video production venue.

Hitoshi Shiozaki

Honorary President

Yoshihiko Hosoi

President

Hisashi Fujihara

Professor

SPring-8
Planning
Yoshiyuki Amemiya

President of Japan Synchrotron Radiation Research Institute (JASRI)

Tetsuya Ishikawa

Director of RIKEN SPring-8 Center(RSC)

Hikaru Takaya

Kyoto Univ.

Kunihisa Sugimoto

Japan Synchrotron Radiation Research Institute (JASRI)

Yusuke Tamenori

Japan Synchrotron Radiation Research Institute (JASRI)

Ichiro Hisaki

Osaka Univ.

Masatoshi Takao

Osaka Univ.

Takafumi Ueno

Tokyo Institute of Tchnology

Hironori Higashi

RIKEN SPring-8 Center(RSC)

Rie Okinishi

RIKEN SPring-8 Center(RSC)

Production
Shogo Kawaguchi

RIKEN SPring-8 Center(RSC)

Yoshinori Kotani

RIKEN SPring-8 Center(RSC)

Tomoya Uruga

RIKEN SPring-8 Center(RSC)

Kazuya Hasegawa

RIKEN SPring-8 Center(RSC)

Kentaro Uesugi

RIKEN SPring-8 Center(RSC)

Masahiro Yasutake

RIKEN SPring-8 Center(RSC)

Masayuki Uesugi

RIKEN SPring-8 Center(RSC)

Motohiro Suzuki

Kwansei Gakuin Univ.

Mizuki Tada

Nagoya Univ.

275

Special Thanks to Various Contributions
Videos for the practical examination
Kyoto Prefectural Sagano High School
Kyoto Prefectural Ohki High School

Planning and Management
Tomokazu Mizuno

KNT Corporate Business Co., Ltd.​kaori Takanashi

KNT Corporate Business Co., Ltd.​

Daisuke Kajikawa

KNT Corporate Business Co., Ltd.​

Yumiko Ishibashi

KNT Corporate Business Co., Ltd.​

Sayuri Noda

KNT Corporate Business Co., Ltd.​

Risa Tanaka

KNT Corporate Business Co., Ltd.​

Riko Nakabayashi

KNT Corporate Business Co., Ltd.​

Yuka Nakamura

KNT Corporate Business Co., Ltd.​Video courtesy
Kyoto Convention & Visitors Bureau
Osaka Convention & Tourism Bureau​

Filming cooperation
Gangoji temple

Congress Center
Miyako Hotel Kyoto Hachijo

Establishment and management of a examination system by Zoom
Hirokazu Shimizu

Shimizu C&S Co., Ltd.

Editing/Printing/Overseas Distribution
Kumiko Shibata

MITSUBA TOTAL PRINTING CO.,LTD.

Establishment and management of Web site
Naomi Hatakeyama

276

ISC Co., Ltd.

The 53rd IChO 2021 Japan

Special Thanks to Various Contributions
Character design/Catalyzer design
Hayanon

HAYANON SCIENCE MANGA STUDIO

Catalyzer Editing and proofreading
Keiko Tahara

Translation/English correction
Maiko Katayama

English correction
Tony Atkinson
Rader Jensen

Medal Design
Misaki Nishizawa

HAKUHODO PRODUCT’S INC.

Secretariat support
Sonomi Takamatsu

277

See youin China

July 10 ~ 18, 2022 (Remote)See you also in the future
host countries
2023 Zurich, Switzerland
July 16~252024 Riyadh, Saudi Arabia
2025 Dubai, United Arab Emirates

inorganic antibacterial agent,
Coating on cover
JP0122233A0001P