ACS, March 21, 2022

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Discovery of the element nipponium in 1908
and its Re-assignment to rhenium
Yoshi Maeno @ Kyoto University(October 2021)

Ehime PrefecturalScience Museum

Genesis ResearchInstituteKyoto University① Motivation: Issues over nipponium and rhenium② Ogawa’s discovery of nipponium③ Yoshihara’s identification of “nipponium” as rhenium④ Our new evaluation of “nipponium” as rhenium (75 Re)

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Introduction: at Mendeleev 150 conference (July 2019, St. Petersburg)
Japan: 日本 (Nihon or Nippon, both accepted)
Element 113 Nh (nihonium)

Japan = 日本 = Nippon OR Nihon
Dr. Enyo gave a plenary talk on nihonium 113 Nh.
Morita, EnyoThen, Dr. Eric Scerri commented：“There is only weak evidence that Ogawa’snipponium was rhenium. I do not believe in thatclaim.”
In fact, there are some reasons why Ogawa’s
work was not well evaluated yet.
We decided to re-evaluate previous studies.

Maeno, Scerri, Seaborg

Issues to assign Ogawa’s nippoium as rhenium

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1. Is there solid evidence for rhenium?
2. Is it really possible to extract nearly 100 mg of rhenium from thethorianite mineral?
3. Why did Ogawa not report on detailed properties of nipponium
after his first three papers, especially on X-ray spectroscopic evidence
that became available in later years?
4. Why did Ogawa not re-assign nipponium as the element 75 himself
even after the report by the Noddacks? And why did Ogawa’s colleagues
in Japan not report on such a re-assignment even after Ogawa’s death?
5. Why is the absence of rhenium in the zirconium silicate often used as
evidence against Ogawa’s discovery?

International recognitions of Ogawa’s nippoium as rhenium

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Negative recognitions in the past:・Hevesy (1925)
The silicate (supposedly) containing the new element nipponium, provided by Mr. R.-B.
Moore, were composed, essentially, of zirconium silicate having a content of 2% of hafnium.
・Noddack et al. (1925)
They claimed the discovery of elements 43 (masurium) and 75 (rhenium), but did notcite Ogawa’s work.
・Van Spronsen (1969)
He quoted Hevesy’s report and continued that Ogawa’s report did not satisfy thechemical properties to identify nipponium to hafnium.

Modern positive recognitions:・Theodore Gray (2009) The Element
・Fontani et al. (2015) The Lost Elements,
They also criticize Western science community to accept Hevesy’s misunderstanding.
・Peter van der Krogt “Elementymology & Elements Multidict” website
・ The Royal Society of Chemistry (RSC) (2021)
・John Emsley’s book (2011)

Periodic-Table website

“Periodic Videos” by Professor Sir Martyn Poliakoff (Univ. of Nottingham)
Nipponium - The Element that Wasn’t –Periodic Table of Videos
2021/12/13 (7:10) viewed 308,979 times

Nagayasu Nawa

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Very surprisingly there have been hugearguments did Ogawa discover rhenium.

Japan = 日本 = Nippon OR Nihon

Special exhibition andcitation in a very well-known newspaper column in Japan

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Special exhibition
at Ehime PrefecturalScience MuseumOct. - Nov. 2020
Co-author
Yuji Hisamatsu
Asahi
Newspaper
On the top page2021/11/18
Ogawa andnipponium

Masataka Ogawa (1865 – 1930)

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1865 Born in Ehime
1889 Graduated from Imperial University (Univ. of Tokyo today)
1889 Entered its graduate school (advisor: Edward Divers)
1904 – 1906 Studied under William Ramsay*
at University College London (UCL)* Ramsay: 1904 Nobel Prize in Chemistry
for his discovery of noble-gas elements
Masataka Ogawa(1865 ‒1930).
Taken in ca. 1911

1908-1909 Published papers reporting the new element
nipponium Np, assigned as the element 43.
1911 - Dean of the College of Science at Tohoku Imperial
University (Tohoku Univ. today, in Sendai)
1919 - President of Tohoku Imperial University
1930 Died of gallbladder disease

Periodic Tables as of 1905
Dmitri Mendeleev
Principles of Chemistry,
3rd ed., Longmans(1905) .

Alfred WernerBericht. 38, 914-921 (1905).

3d4d5dTokyo Electron

43 Tc technetium (1937 - )75 Re rhenium (1925 - )

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Ogawa’s papers on nipponium(I) Ogawa, M.: “Preliminary Note on a New Element in Thorianite”.
J. Coll. Sci. Imp. Univ. Tokyo 25, Art. 15, 1–11 (1908a)(reprinted in Chem. News 98, 249-251 (1908))(II) Ogawa, M.: “Preliminary Note on a New Element allied to Molybdenum”.
J. Coll. Sci. Imp. Univ. Tokyo 25, Art. 16, 1–13 (1908b)(reprinted in Chem. News 98, 261-264 (1908))(III) Ogawa, M.: “On New Elements in Thorianite”.
J. Chem. Soc. Tokyo 30, 1277–1299 (1909)(only in Japanese)(III) 1909

nipponium by Ogawa
element Z = 43 ➡ Noddaks (1925) ➡ Tc (1937)
symbol Np ➡ neptunium Z = 90 (1940)
113 nihonium NhJapan = 日本
= Nippon OR Nihon

What did Ogawa actually found?
Full chemical processesof the main extraction 10/19

Thorianite mineral

Thorianite typically contains:
ThO2: 78.0%
UO2 : 14.5%
Si, Pb, Fe, Cu, Al, Sc, Ce, Zr: 6.5%
Ca, P, Co, Hg, Sb, Bi, Sn, As, Ti, etc.: 1.0%

Ogawa’s attempts to identify nipponium

11/19“Ogawa’s Nipponium and Its Re-assignment to Rhenium”
Y. Hisamatsu, K. Egashira, Y. Maeno, Found. Chem. (Oct. 2021) DOI: 10.1007/s10698-021-09410-x
Chemical processes Ogawa adopted to convert
nipponium hydroxide to the oxide, chloride, and sulfate.

Thorianite mineral

Ogawa’s attempts to identify nipponium

12/19“Ogawa’s Nipponium and Its Re-assignment to Rhenium”
Y. Hisamatsu, K. Egashira, Y. Maeno, Found. Chem. (Oct. 2021) DOI: 10.1007/s10698-021-09410-x

Chemical processes Ogawa adopted to convert
nipponium hydroxide to the oxide, chloride, and sulfate.
From the mass ratios of the oxide, chloride, and sulfate,Ogawa deduced the atomic mass of 100 for nipponium,and concluded it as the element 43.

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Recognition of nipponium as rhenium by Yoshihara (1996)

Ogawa (1908) assumed that Np (nipponium) was divalent,
deduced the atomic weight of 100, and concluded the element as 43rd.
Instead of divalent NpO, NpCl2, NpSO4,
Yoshihara assumed hexavalent RO3, (RO)ClO4, (RO)(SO4)2.
Then, the values in Ogawa’s papers lead to the atomic weight of 75Re.
Note that Yoshihara assumed (RO)Cl4, NOT RCl6.
Kenji Yoshihara(Prof. Emeritus,Tohoku University,1929 - )Yoshihara found the X-ray
photographic plate of 1930 that
had been kept by Ogawa’s family.
Yoshihara recognized a strong
peak of Re.

Yoshihara, H.K.:

Yoshihara also collected alarge variety of evidence
on Ogawa’s nipponium,including oral evidence
from Ogawa’s colleagues.

“Nipponium, the Element Ascribable
to Rhenium from the Modern Chemical Viewpoint,”
Radiochim. Acta 77, 9-13 (1997).
“Nipponium as a new element (Z = 75) separated
by the Japanese chemist, Masataka Ogawa:a scientific and science historical re-evaluation”,
Proc. Jpn. Acad. B 84, 232-245 (2008).

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Key compounds in Ogawa’s study

Key compounds and reactions to obtain the equivalence in Ogawa’s paper,compared to Yoshihara’s and our re-assignments.
Conversions

Mass ratio (g)Ogawa (1908)

Yoshihara (1997)

Our paper

Hydroxide to Oxide

̶Np(OH)2 / NpO

ReH2O3 / (ReO2 + Re2O7)

Re2O7(OH2)2 / ReO3

“Chloride” to Oxide

0.1092 / 0.0742

NpCl2 / NpO

ReOCl4 / (ReO2 + Re2O7)

ReOCl4 / ReO3

Sulfate to Oxide

0.1253 / 0.0747

NpSO4 / NpO

ReO(SO4)2 / (ReO2 +Re2O7)

ReO(SO4)2 / ReO3

“Chloride” to AgCl

0.0652 / 0.1120

NpCl2 / 2AgCl

ReOCl4 / 2AgCl

ReOCl4 / 2AgCl

Y. Hisamatsu, K. Egashira, Y. Maeno,
Found. Chem. (Oct. 2021)
DOI: 10.1007/s10698-021-09410-x

Re2O7

ReO3

ReO2

Optical emission spectrum of 75Re (rhenium)

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Y. Hisamatsu, K. Egashira, Y. Maeno,
Found. Chem. (Oct. 2021) DOI: 10.1007/s10698-021-09410-x

Ogawa’s description (1908) for his nipponium sample:“three spectral lines in the green-blue region
with the strongest peak at 4882 ± 10 Å”.

Optical spectrum of rhenium
based on Meggers (1931).
The strongest peak at 4889.2 Å.

This is essentially different from reports claiming new elements based on
their X-ray spectra after the “correct answer” became known beforehandfrom Moseley’s law (1913).

X-ray spectrum of Ogawa’s nipponium sample

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It shows an unusual spectral shape.
Instead of a peak, a pair of
positive and negative peaksappears.
It must have been a “Differentialoutput” of a peak signal.
Photographic plate of the X-ray spectrum by S. Aoyama at Tohoku Imperial Univ.
(1930). Reference elements were added to the “nipponium” sample by Ogawa.
Siegbahn-type
X-ray Spectrometer
Became available in Japan
in 1929-1930.
From Shibata, Mizushima,Kimura,“Spectral Chemistry” (1945).

X-ray spectrum of Ogawa’s nipponium sample

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Spectrumby Aoyama(1930)

Red: Simulated differential-peak spectrum with anticipated intensity ratios.
Y. Hisamatsu, K. Egashira, Y. Maeno,
Found. Chem. (Oct. 2021) DOI: 10.1007/s10698-021-09410-x

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Why Ogawa and his colleagues could not re-assigne nipponium as rhenium
By the chemists in Japan

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At least a few chemists who most probably knew that nipponium was rhenium
never published such results even after Ogawa’s death.
The science in Japan was not matured enoughConsidering the imperial fame Ogawa received, it must have been difficult todisclose the unwanted truth in that period in Japan.
By Ogawa himself
1906–1912: during the publications
1913–1925: before the report by the Noddacks
1925–1930: after the report by the Noddacks
We explained how Ogawa’s work was often incorrectly cited and we attributed suchmisunderstanding to the fact that he published some key results only in Japanese.
As a scientist who searches for and identifies a new element.
Ogawa’s strength: his superb ability to extract minute element contents from theminerals by traditional wet-chemistry processes.
Ogawa’s weakness: he insisted on such an approach alone and did not organize ateam with multiple expertise necessary to identify new elements.
It must have been Ogawa’s insistence to search for the 43rd element that prevented
him from reconsidering the re-assignment as the 75th element perhaps until justbefore his death in 1930 (when he was told about the results of X-ray spectra) .

Conclusions

19/19“Ogawa’s Nipponium and Its Re-assignment to Rhenium”
Y. Hisamatsu, K. Egashira, Y. Maeno, Found. Chem. (Oct. 2021) DOI: 10.1007/s10698-021-09410-x

We have reexamined the works by Ogawa and Yoshihara and conclude thatOgawa’s nipponium is indeed re-assigned to the 75th element, rhenium (Re).

(0) We made detailed diagrams of the chemical processes,
described in Ogawa’s papers only in words.
(1) The weight changes reported by Ogawa,after interpreted with the actual chemical reaction,lead to the correct atomic weight of rhenium.
(2) The optical emission spectrum describedby Ogawa is consistent with that of rhenium(3) The X-ray photographic plate for a nipponium
sample shows clear peaks of rhenium.
(4) We examined the reasons why Ogawa himself
and his colleagues could not identify nipponium
as the 75th element (Re).

Thank you.