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National Bureau of Standards

Library, E-01 Admin. Bidg.

OCT 6 1981

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^^'^fAU Of ^

/^^ |\IBS TECHNICAL NOTE 1112

U.S. DEPARTMENT OF COMMERCE/ National Bureau of Standards

30

5753

D. 11121

980
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act ot Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and

the Institute for Computer Sciences and Technology.

THE NATIONAL MEASUREMENT LABORATORY provides the national system of

physical and chemical and materials measurement; coordinates the system with measurement

systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific community, industry,

and commerce; conducts materials research leading to improved methods of measurement,

standards, and data on the properties of materials needed by industry, commerce, educational

institutions, and Government; provides advisory and research services to other Government

agencies; develops, produces, and distributes Standard Reference Materials; and provides

calibration services. The Laboratory consists of the following centers:

Absolute Physical Quantities^ — Radiation Research — Thermodynamics and

Molecular Science — Analytical Chemistry — Materials Science. THE NATIONAL ENGINEERING LABORATORY provides technology and technical ser- vices to the public and private sectors to address national needs and to solve national problems; conducts research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary disciplines required to carry out this research and technical service; develops engineering data and measurement capabilities;

provides engineering measurement traceability services; develops test methods and proposes

engineering standards and code changes; develops and proposes new engineering practices;

and develops and improves mechanisms to transfer results of its research to the ultimate user. The Laboratory consists of the following centers:

Applied Mathematics — Electronics and Electrical Engineering- — Mechanical

Engineering and Process Technology' — Building Technology — Fire Research —

Consumer Product Technology — Field Methods.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts

research and provides scientific and technical services to aid Federal agencies in the selection,

acquisition, application, and use of computer technology to improve effectiveness and

economy in Government operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing the Federal Information Processing Standards Program, developing Federal ADP standards

guidelines, and managing Federal participation in ADP voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and

provides the technical foundation for computer-related policies of the Federal Government.

The Institute consists of the following centers:

Programming Science and Technology — Computer Systems Engineering.

'Headquarters and Laboratories at Gaithersburg, MD, unless otherwise noted; mailing address Washington, DC 20234. ^Some divisions within the center are located at Boulder, CO 80303.
ow avAaniABDs

tlBBABT

JUN 2 5 1980

I" lot a. User Evaluation of Crystal Data Products ^co.

and Services: Questionnaire Analysis and Impact n^^/nt

J. K. Stalick

A. D. Mighell

R. J. Boreni

Center for Materials Science

National Measurement Laboratory

National Bureau of Standards

Washington, DC 20234

.^< °'>.

U.S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary

Luther H. Hodges, Jr., Deputy Secretary

Jordan J. Baruch, Assistant Secretary for Productivity, Technology and Innovation

^.NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued June 1980
National Bureau of Standards Technical Note 1112

Nat. Bur. Stand. (U.S.), Tech. Note 1112, 42 pages (June 1980) CODEN; NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1980

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Price $2.25

(Add 25 percent additional for other than U.S. mailing)
TABLE OF CONTENTS

Abstract 1

1.0 Introduction 1

2.0 Analysis of Response 2

2.1 Description of Respondent 2

2.1.1 Type of Work and Employer 2

2.1.2 Type of Diffraction and Materials . . . .

• 4

2.1.3 Name and Address of Employer and Respondent 5

2.2 Use of Crystal Data 8

2.2.1 Use of Crystal Data Determinative Tables 8

2.2.2 Duplication of Crystal Structures and Unit Cell Determinations . . 9

2.2.3 Specific Applications of Crystal Data Determinative Tables .... 10

2.2.3.1 Materials Analysis and Qualitative Identification .... 11

2.2.3.2 Research Applications 11

2.2.3.3 Isostructural Materials and Assignment

of Structure Type 12

2.2.4 Use of the Single-Crystal Method and the Powder Method

of Identification 12

2.2.5 Use of Crystal Data Space-Group Tables 14

2.2.6 Suggestions for Improvement of Crystal Data Determinative Tables 15

2.2.7 Evaluation of Data Prior to Publication 16

2.2.8 Assistance to the Crystal Data Project 16

2.3 Supplementary Content of Crystal Data Entries 16

2.4 Literature Coverage 17

2.5 NBS Crystal Data Center Published Products ... 18

2.6 Crystal Data File Searches and Analyses 20

2.6.1 Computer-Based Methods of Dissemination 20

2.6.2 Research Using a Computer Data File 21

3.0 Summary of Results and Conclusions 21

Appendix A. Questionnaire on Crystal Data 24

Appendix B. Specific Areas of Application of Crystal Data Determinative

Tables 31 Appendix C. Applications of Crystal Data Space-Group Tables and Nowacki's

Systematic Tables 37

iii

USER EVALUATION OF CRYSTAL DATA PRODUCTS AND SERVICES: QUESTIONNAIRE ANALYSIS AND IMPACT

J. K. Stalick, A. D. Mighell, and R. J. Boreni

Center for Materials Science

National Measurement Laboratory

National Bureau of Standards

Washington, D. C. 20234

A survey was made of the needs of the users of Crystal Data Determinative Tables

and related products and services of the NBS Crystal Data Center. The results

indicate a high frequency of use of Crystal Data , with particular application to materials analysis and design. The survey suggests a need for the development of

a rapid and inexpensive method of unit-cell determination as well as education of

the scientific community in the use of the single-crystal method for identification

of unknown materials. More complete coverage and consolidation of entries are also

suggested. The necessity for computer-based methods of data base dissemination is

indicated, with particular importance for research applications.

Key Words: Computer dissemination; Crystal Data; identification; materials analysis;

materials design; NBS Crystal Data Center; user evaluation.

1 .0 Introduction

The NBS Crystal Data Center is responsible for the evaluation and compilation of crystallographic data on inorganic substances for which unit-cell data have been reported, and

for the dissemination of data on both organic and inorganic substances to the scientific

community. This activity is in accordance with the Standard Reference Data Act of 1968,

which states in Section 1 that "The Congress hereby finds and declares that reliable standardized scientific and technical reference data are of vital importance to the progress of

the Nation's science and technology. It is therefore the policy of the Congress to make

critically evaluated reference data readily available to scientists, engineers, and the

general public." The Crystal Data Center is sponsored jointly by the Office of Standard

Reference Data and by the Ceramics, Glass, and Solid State Science Division of the Center

for Materials Science.

The principal output of the Crystal Data Center has been the publication of Crystal

Data Determinative Tables . In 1978 Volumes 3 and 4 of the 3rd Edition series were published

jointly by the U. S. Department of Commerce, National Bureau of Standards, and the JCPDS--

International Centre for Diffraction Data. In the Determinative Tables the compounds are ordered by crystal system and by Crystal Data cell ratios. The ' rystal Data Space-Group

Tables , published in 1977 in the Journal of Physical and Chemical Reference Data , contains

a tabulation of compounds appearing in Volumes 1 and 2 of the Determinative Tables arranged

by space group, and the Crystal lochemical Identification Tables (in preparation) will contain all compounds in the Crystal Data File ordered by reduced cell parameters.

In the eleven years since the Standard Reference Data Act was passed, the demand and

need for standard reference data as compiled and evaluated by experts at various data centers has increased substantially. There are three main reasons for this:

(1) Data explosion . Standardized and critically evaluated data subsets are essential

because the entire set of physical and chemical data is so large that it is not subject to facile evaluation and dissemination. Chemical Abstracts has now registered 5 million compounds, with a yearly increase of 360,000 substances. Only

the data centers can deal in a meaningful way with specified subsets of this data.

1
(2) Quality improvement . Data centers have developed sophisticated computer algorithms to evaluate published data, in addition to evaluation by experts in the

field. Errors are detected and corrected so that the compiled data are significantly better than the data in the primary literature. Such evaluated data are invaluable for scientific research and computer modeling.

(3) Data dissemination . Recent developments in computer hardware and software have

totally changed the way in which data can be disseminated. Computer-based data

files make possible a much closer interaction between the data center and the user (e.g. it is possible to supply any desired subset of the data base) and

greater interaction among various data centers to permit the merging of selected

data parameters. Computer methods also make possible the rapid on-line dissemination of data throughout the United States, as well as the incorporation of the

data base directly into the instrument that collects the data. In addition,

research using the evaluated data sets is possible through the use of data base

management systems.

The NBS Crystal Data Center is now in a period of transition from a hand-based to a computer-based operation. This will permit a second transition from emphasis on a single

product to a variety of products and modes of data dissemination. The questionnaire on Crystal Data was designed to gain the information required to assist the Crystal Data Center

in this transition stage, particularly with respect to the design and content of the new computer file structure. In view of the limited resources available for the data compilation effort, it was deemed necessary to obtain information on the cost-effectiveness of the

inclusion of various data items and products and to set priorities for the allocation of

these resources while still meeting the prime needs of the users. An additional benefit

would be the location of users willing to help with the Crystal Data project.

Consequently a survey was conducted to find out who the users are, what data they want,

the products and services they want, and how they use crystal lographic data in their work.

This information will be of great value in determining the directions in which the NBS

Crystal Data Center should concentrate its efforts.

2.0 Analysis of Response

The questionnaire was distributed in December of 1978 and January of 1979 by the NBS

Associateship of the JCPDS-International Centre for Diffraction Data. Since no mailing list

of users or purchasers of Crystal Data existed, the questionnaire mailing list was selected

from that of the JCPDS and, in a few cases, from the World Directory of Crystal lographers

(Fifth Edition, 1977). The total number of questionnaires distribute3~was 1058. The number

returned was 235, or 22%. Taking into account the difficulty in compiling the mailing list,

the out-of-date addresses of the recipients (many addresses on the list were more than 10

years old), and the extreme length of the questionnaire, this represents a remarkable return

rate and indicates a high degree of interest in the Crystal Data publications.

The questionnaire was divided into six sections. The first section requested information describing the respondent. The next three sections dealt with the use and content of

Crystal Data publications, and the final two sections concerned published products and com- puter-based distribution of the NBS Crystal Data File. A copy of the questionnaire is given

in Appendix A, with a summary of the answers shown for each question.

2.1 Description of Respondent

The first seven questions requested information on nature of employment and personal

data. In all cases the totals add up to greater than 100% of those responding, as one or more categories could be checked.

2.1.1 Type of Work and Employer

Most respondents classified their type of work as basic research (71%) and/or applied

research (44%), with significant numbers also involved in education (33%) and analysis (26%)

(Table 1). The types of employers are given in Table 2, with university or college (43%)

and industrial (37%) predominating.
Table 1. Present Type of Work (1-1)*

Category Number of Respondents (%)

Basic research 168 (71%)

Applied research 104 (44%)

Education 78 (33%)

Analysis 62 (26%)

Product development 29 (12%)

Quality control 19 ( 8%)

Production 13 ( 6%)

Othera 8 ( 3%)

^Catalyst development, consulting, customer service, data base production,

legal, production support, student, trouble shooting.

Table 2. Type of Employer (1-2)

Category Number of Respondents (%)

University or college 102 (43%)

Industrial 86 (37%)

Government 37 (16%)

Research institute 11 ( 5%)

Othera 5 ( 2%)

^Clinical laboratory or hospital (2), emeritus, non-profit technical services

to government, personal consultant.

The respondents were asked to characterize their employer further by checking one or more of a group of listed Standard Industrial Categories (SIC), with the results given in

Table 3. The results indicate a broad range of industrial classifications, with educational

services (97 responses) and chemicals and allied products (51 responses) predominating.

Forty-three respondents checked the box "Other [please describe]" and their descriptions are

also given in Table 3.

Table 3. Standard Industrial Categories of Employer (1-3)

Number of

SIC No. Category Times Checked

82 Educational services 97

28 Chemicals and allied products 51 36 Electrical and electronic equipment 18

32 Stone, clay, glass, & concrete products 16

34 Fabricated metal products 13

80 Health services 12

97 National security and international affairs 12

14 Mining of nonmetallic minerals 8

33 Primary metal industries 8 12 Bituminous coal and lignite mining 7 29 Petroleum refining 6 95 Environmental quality and housing 6 10 Metal mining 5 13 Oil and gas extraction 5

* Numbers in parentheses indicate question number.
Table 3 (continued)

38 Instruments and related products 5 35 Machinery, except electrical 4 84 Museums, art galleries, botanical and zoological 3 gardens

91 Executive, legislative, and general government 3

11 Anthracite mining 2 81 Legal services 1 92 Justice, public order, and safety 1 Other^ 43

^The following descriptions of industrial categories were given:

Energy research (6 responses)

Government basic research (4 responses)

Communications (3 responses)

Research in earth sciences (USGS) (3 responses)

Pharmaceuticals (2 responses)

Photographic materials (2 responses)

Polymer products (2 responses)

Refractory materials (2 responses)

Textiles (2 responses)

Aerospace products

Automotive

Biochemistry - pharmacology

Consulting services

Contract research

Crystal growth for optical uses Explosives research

Extractive metallurgy - corrosion - resource recovery

Manufacturing

Materials research

Metallurgy research and secondary materials research

Military

Nuclear energy

Ore processing

Plutonium metallurgy

Soap and detergent industry

Stimulation and support of basic research (granting agency)

2.1.2 Type of Diffraction and Materials

The respondents were also asked to characterize their work by the type of diffraction

and type of materials involved in their work, with the results given in Tables 4 and 5. Both x-ray powder diffraction and single-crystal diffraction were checked as being used by

80% and 71%, respectively, of the respondents, while the types of materials involved were

primarily inorganics and minerals (Table 5).

Table 4. Type of Diffraction Used (1-4)

Type Number of Respondents (%)

X-ray powder diffraction 189 (80%)

X-ray single-crystal diffraction 167 (71%)

Electron diffraction 44 (19%)

Neutron diffraction 21 ( 9%)
Table 5. Type of Materials Used (1-5)

Type Number of Respondents (%)

Inorganics 177 75%)

Minerals 118 50%)

Organ ics 81 34%)

Ceramics 73 ( 31%)

Metals and intermetallics 67 29%)

Small molecules 64 < 27%)

Organometall ics 59 25%)

Catalysts 51 ( 22%)

Drugs 29 12%)

Large molecules or proteins 21 . 9%)

Pesticides and herbicides 13 6%)

Other^ 14 : 6%)

Polymers (3 responses), corrosion products (2 responses), explosives

(2 responses), air pollutants, biological molecules, environmental mate- rials, gaseous samples, metal salts of organics, natural products especially toxins, high explosive radioactive materials.

2.1.3 Name and Address of Employer and Respondent

The name and address of the employer were given by 177 (75%) of the respondents, and

these are given in Table 6. In addition, 169 (72%) listed their own name and address,

indicating a willingness to be contacted for further information (question 1-7).

Table 6. Personal Employment Data (1-6)

Industrial

AMP Inc. Abbott Laboratories

Allied Chemical Corp. (2)

Basic Inc. Bell Telephone Laboratories, Inc. (2)

Borg-Warner

Cleveland Crystals, Inc. Corning Glass Works

Dow Chemical Co. (3)

Dow Corning Corp.

Dresser Industries, Canadian Refractories Division

E. I. du Pont de Nemours & Co. (5)

Eastman Kodak Co. (2)

Engelhard Industries

Exxon Research and Engineering Co. Ford Motor Co. GTE Laboratories (2)

GTE Sylvania

General Electric

B. F. Goodrich Co. Gould Inc.

W. R. Grace and Co.

A. P. Green Refractories Co. The Harshaw Chemical Co. Louis C. Herring & Co. Hoffmann-LaRoche

Lockheed Research

The Lubrizol Corp.

3M Co.
Table 6 (continued)

Medtronic 5 Inc.

01 in Corp.

PPG Industries, Inc. Phelps Dodge Corp.

Phillips Petroleum Co. Polaroid Corp.

The Procter and Gamble Co. (2)

RCA Corp.

Raychem Corp.

Reynolds Metals

Rockwell International (2)

Shell Development Co. Sherwin-Williams Co. Sperry Research Center

J. P. Stevens & Co., Inc. Sun Production Co. Thiele Kaolin Co.

U. S. Steel

Union Carbide Corp. (2)

Union Oil Co. of California

Upjohn Co. Warner Lambert/Parke Davis

University or College

Baylor University

Bethune-Cookman College

Brigham Young University

Brown University

California Institute of Technology

Carnegie-Mellon University

Case Western Reserve University

Colorado School of Mines (2)

Cornell College

Georgia Institute of Technology

Harvard University

Huston-Tillotson College

Indiana University

Iowa State University (2)

Johns Hopkins University

Loyola University

McGill University (2)

McMaster University

Menlo College

Michigan State University (2)

Montana State University

The Ohio State University

Pennsylvania State University

Portland State University

Purdue University

Queen's University

Roanoke College

Rutgers University

Simon Fraser University

State University of New York at Buffalo (3)

Texas A&M University (3)

University of Alaska

University of Arizona

University of British Columbia

University of California at Berkeley

University of California at Los Angeles
Table 6 (continued)

University of Cambridge

University of Chicago (4)

University of Colorado (2)

University of Connecticut

University of Heidelberg

University of Illinois at Chicago

University of Iowa University of Louisville

University of Michigan

University of Minnesota

University of Nebraska

University of New Brunswick, Fredericton

University of New Hampshire

University of North Carolina

University of Oregon

University of Pittsburgh

University of Rhode Island

University of Southern California

University of Vermont

University of Virginia

University of Waterloo

University of Wisconsin at Milwaukee

University of Wyoming

Vanderbilt University

Virginia Polytechnic Institute & State University

Wake Forest University

Government and National Laboratories

Air Force Office of Scientific Research

Argonne National Laboratory

Armament Research and Development Command (ARRADCOM)

Brookhaven National Laboratory

Geological Survey of Canada

Institute of Forensic Sciences

Lawrence Berkeley Laboratory

Lawrence Livermore Laboratory (2) Los Alamos Scientific Laboratory

National Aeronautics and Space Administration

National Research Council of Canada (2)

Naval Research Laboratory (4)

Naval Surface Weapons Center, White Oak Laboratory

Oak Ridge National Laboratory (2)

Sandia Laboratories (4)

U. S. Army Engineer Waterways Experiment Station

U. S. Bureau of Mines (2)

U. S. Geological Survey (4)

Research Institutes

Battel le Northwest Laboratories

Colorado School of Mines Research Institute

Denver Research Institute

Midland Macromolecular Institute

Royal Ontario Museum

Other

The Aerospace Corp.

Mt. Sinai Hospital
2.2 Use of Crystal Data

In this section eleven questions were asked concerning the use of Crystal Data Determinative Tables and Crystal Data Space-Group Tables .

2.2.1 Use of Crystal Data Determinative Tables

Question II-l asked, "How often do you use Crystal Data Determinative Tables in the

following way [use 3 = frequently, 2 = occasionally, 1 = rarely, = not at all]". Of the

212 respondents answering all or part of this question, 103 (49%) use Crystal Data frequently

in one or more ways, and another 92 (43%) use it occasionally. Only 17 respondents (8%)

reported that they use Crystal Data rarely. Also, 172 respondents (81%) reported occasional

or frequent use in more than one category, so that the combined usage is high. The responses

indicating relative frequency of use are summarized in Table 7.

It can be seen that Crystal Data is most commonly used as a reference book, primarily to obtain structural information; that is, to find cell dimensions, to find out if a particular

structure has been determined, or to obtain information about structure types. It is used to identify unknown substances using the determinative ratio less often. Seventeen respondents

checked the box marked "other" and their responses are also given in Table 7.

Table 7. Use of Crystal Data Determinative Tables (II-l)

Number of Respondents Average Rating^ Type of Use

212 1.8 To find cell dimensions or space group of

a particular substance

211 1.7 To find out if the structure of a particular substance has been determined.

205 1.5 To find information about structure types

or to locate isostructural materials.

209 1.4 To locate literature references containing crystal data on a particular substance

or structural group.

204 1.1 To identify an unknown substance using the

determinative ratio.

202 0.9 To obtain information about physical properties of a substance

17 Other^

In this and succeeding questions the average rating was computed according to the following equation, where N(i) represents the number of times a given response

[3,2,1,0] was checked:

average rating = 3[N(3)] . 2[N(2)] . N(l)

N(3) + N(2) + N(l) + N(0)

The following responses were given:

1. Educational purposes for non-specialists

2. To find the formula of a mineral

3. As a literature stockroom

4. To find similar mineral classifications (e.g. asbestos types)

5. To check out cell dimensions of compounds

8
6. To assist in indexing and generating powder diffraction data when only single

crystal reference data is available

7. For qualitative identification, not using the determinative ratio

8. For phase determinations

9. I use it when I am baffled

10. To determine degree of orientation

11. Basic reference in teaching/research crystallography lab

12. For research [this response is given in full in the discussion of question

II-5]. Much more work of this sort could be based on Crystal Data.

13. In the study of polytypism, e.g. SiC

14. Routine use in characterization of solids

15. To check conventions regarding axial lengths etc.

16. When powder data fails for identification

17. To check powder data and other crystal data quoted in the literature

The next question (II-2) requested information on the areas in which the respondents use

Crystal Data , with the results summarized in Table 8. The type of study checked was predominantly crystal structure analysis (143), with significant use in phase equilibria (53),

materials processing (42), high or low temperature studies (40), corrosion (33), and catalysis (29). The types of materials most frequently checked were ceramics (51) and semiconductors (29), although magnetic materials, optical materials, and energy conversion materials

were also important.

Table 8. Areas of Use of Crystal Data (II-2)

No. of Times Checked Type of Study

143 Crystal structure analysis

53 Phase equilibria

42 Materials processing

40 High or low temperature studies

33 Corrosion

29 Catalysis

17 Fracture or wear studies

17 High pressure studies

16 Diffusion in metals

11 Failure prevention

10 Materials durability

No. of Times Checked Type of Material

51 Ceramic materials

29 Semiconductor materials

23 Magnetic materials

23 Optical materials

20 Energy conversion materials

2.2.2 Duplication of Crystal Structures and Unit Cell Determinations

The next two questions concerned duplication of effort that in many cases could have

been prevented if the appropriate reference data had been consulted or had been available.

Question II-3 asked, "Have you ever solved a structure or collected data and then found that

your work was unnecessary because the same or similar substance had already been solved? If

yes, how often has this happened? What is your dollar estimate of the cost involved (computer time, lost hours, etc.) for each occurrence?" "No" was checked by 159 respondents; of

the 64 respondents who checked "yes", 59 explained further. Table 9 summarizes the number of

structure duplications reported. Of the more than 67 structures redetermined, 10 were commented on as still being of value, and another 10 redeterminations could not have been

prevented as the data had not yet been published. The cost in computer time (excluding

equipment costs and personnel costs) was estimated by 29 respondents, and ranged from $300 to $15,000 per structure with a median of $2000. Only 12 respondents attempted to estimate the

time lost per structure, ranging from "trivial" to "4 years of graduate school", with a median of two v^eeks.
Table 9. Frequency of Crystal Structure Redetermination (II-3)

Number of

Respondents

159

3112

2

154

6

3

Number of Structures

Redetermined

1236

Not given (but checked "yes")

Don't know (but checked "yes")

Not often or occasionally

Others

Once a year; 5% of the time; 1-2 per year.

The respondents were next asked to give the same type of information with respect to the

redetermination of unit cell parameters (rather than complete structure determinations). The

response indicates that the redetermination of cell parameters is not as serious as the

redetermination of a crystal structure. Although the number of unit cell redeterminations

reported was comparable to that reported for crystal structures, several respondents indicated that this in fact represents a saving of time and money as the compound involved was

not what was originally suspected and thus the crystal structure was not duplicated. Of the

63 respondents who checked "yes", 55 commented on the number of occurrences or cost. Table

10 summarizes the number of unit cell redeterminations reported. The cost was estimated by

28 respondents and was an order of magnitude less than that for a crystal structure determination, ranging from $5 to $5000 with a median cost of $200. The time involved was not

indicated.

Table 10. Frequency of Unit Cell Redetermination (II-4)

Number of Number of Cells

Respondents Redetermined

158

12 1 6 2

5 3

2 6 19 Not given (but checked "yes")

7 Not often or occasionally

6 Done for qualitative identification

2 Don't know (but checked "yes")

4 Other^

Several times; 5% of the time; one per year; 3-4 per year

2.2.3 Specific Applications of Crystal Data Determinative Tables

Question II-5 asked the respondents to describe one or more specific applications of

Crystal Data Determinative Tables . The 106 responses were more general than specific, but

provided some very interesting statistics and uses not indicated in the preceding questions.

The responses are given in full in Appendix B, grouped by user categories. An attempt to group the responses into various areas of application is summarized in Table 11.

10
Table 11. Areas of Application of Crystal Data Detenninative Tables (II-5)

Number of

Respondents Area of Application

43 Materials analysis, qualitative identification

20 Aid in research applications

19 Assign structure type, search for isostructural

materials, or find trial structure

8 For literature search or location of cell constants

7 To find out if a structure has been determined

5 As an aid in teaching and design of experiments

4 Othera

See question II-l (3); need for a computer readable data base.

The response indicates that Crystal Data is used in a complex variety of ways, with some users seeking only bibliographic information, some only cell data, some only structure

information, etc. However, the value of Crystal Data as a general purpose reference book

was stressed by several respondents. One professor at a major university gave the following uses: "Educational purpose; to find a compound suitable for basic training of students

in course work. To find possible isostructural or related compounds pertaining to current

research. Many of my colleagues use the Tables, which I keep accessible to them in my

office. There is such a large variety of occasions where the Tables come in handy, I cannot

list them all."

2.2.3.1 Materials Analysis and Qualitative Identification

The most frequent use of Crystal Data is seen to be in the area of materials analysis

and qualitative identification (Table 11). Although the response to question II-l indicated

that Crystal Data is not primarily used to identify an unknown by using the determinative

ratio , many users have some idea of the chemical composition an3use the indexes to locate

possible materials. A consultant for a private firm said in part, "I often have an unknown

crystal for which I have chemical information . . . and limited optical crystallographic data

. . , Using Crystal Data as a source of information I may be able to pick out likely possibilities and be thus aided in choosing the next step towards identifying the unknown."

Two further examples help to illustrate the use of Crystal Data for materials analysis.

A university professor stated, "Local phosphoric acid plant was having trouble with an unknown compound precipitating in pumps and pipes. Was able to identify compound and advise on how to manage settling ponds to avoid problem." Also, an industrial user commented, "We use

our x-ray diffraction mainly to identify reaction compounds which form in refractories while

they are in use. The data is used to suggest refractories which might provide better service

in such applications, or it may aid in the development of improvements in the refractory

products.

In other cases, the investigator does not know what type of material to expect. For example, one university respondent told the following: "We made a high pressure run in an attempt to prepare a specific new compound. An x-ray powder photograph of the result

showed that a reaction had occurred and that none of the original material was present. The

starting elements were Nb and Te. The powder photograph showed a cubic material with a_ = 4.38 to 4.40A. A quick look through Crystal Data revealed that the 'new' material was almost certainly NbN (with the N from BN in reaction chamber)." In another case, a user at

a large manufacturing company said, "A small (approximately lOOOA) crystallite was isolated

in a piece of human tissue. The crystal provided an electron diffraction pattern. Only

elemental information and two-dimensional diffraction data [were available]. The crystallite was identified with the aid of Crystal Data ."

2.2,3.2 Research Applications

Another major area of use of Crystal Data is in research applications (see Table 11).

11
A primary crystal lographic research area involves structure types and relationships. One

respondent indicated the importance of Crystal Data in this field with the following comments: "Enclosed are reprints of two papers in which references to Crystal Data play an important part. The paper on formates shows some of the shortcomings of Crystal Data

[inconsistent data on rare-earth formates in Crystal Data was the impetus for further

structural work], and the paper on the F51 type shows how much information can be gleaned

from Crystal Data [various structure types reported were explained on the basis of information given in Crystal Data] . Much more work of this sort could be based on Crystal Data ."

Several other examples were given in which the structural relationships found in

Crystal Data can be used in materials research. These include the following three responses,

each from a representative of a major industrial corporation: (1) "A search for a number

of isotropic substances was desired. Searching in the cubic section was most useful,

yielding many compounds which fit our particular needs." (2) "[ Crystal Data was used to]

look for oxides having spinel structure and having lattice parameter within a certain

range. These spinels would be possible substrates for epitaxial growth of other compounds."

(3) "Searched for all compounds crystallizing with a given a^ and b^ dimension (indeterminate)

and a given angle between a^ and b^ for use in layer stacking studies."

The responses also indicate other areas of research in which the information contained

in Crystal Data is useful. These include theoretical calculations, bonding electron distribution studies, interpretation of radial distribution functions and extended x-ray absorption fine structure data, correlation of polytypes with luminescence of SiC, and calculation

of theoretical powder patterns.

2.2.3.3 Isostructural Materials and Assignment of Structure Type

The third major area of use of Crystal Data given in Table 11 is to assign a structure

type, to search for isostructural materials, or to find a trial structure for a crystal

structure determination. A typical response was, "Having a unit cell, I would use the

Tables to see if the structure could be easily guessed by comparing it to known compounds."

The following two comments were from university professors: (1) "A new mineral, maricite,

NaFePOit, had its structure determined by careful checking against axial ratios and cell

dimensions of similar compounds." (2) "[ Crystal Data was used] to determine if a cubic

organomercury compound had been reported. Found that cell edge and space group were identical to that of Ba(N03)2. Powder patterns proved to be practically identical. These data were used to determine the most probable arrangement of the ligands in the unknown."

The remaining areas of application of Crystal Data given in Table 11 are primarily

bibliographic. These include using Crystal Data to find literature references or cell

dimensions, to find out if a structure has been determined, and to aid in teaching and the

design of experiments.

2.2.4 Use of the Single-Crystal Method and the Powder Method of Identification

The next two questions dealt with the use of the single-crystal method and the powder

method of identification. Question II-6 asked, "Do you need to identify unknown crystalline

substances in your work? If yes, do you rely mainly on the powder method (ASTM-JCPDS file)

or the single-crystal method?" Thirty respondents checked "no". Of the 200 respondents who

checked "yes", most relied primarily on the powder method of identification. The results

are given in Table 12.

Table 12. Use of the Single-Crystal Method and the Powder Method (I 1-6)

Number of

Respondents Method of Identification Used

105 Use mostly powder method but also

use Crystal Data for confirmation

or for literature references

60 Use powder method exclusively

46 Use primarily single-crystal method

12
In an attempt to find out why the powder method is preferred for identification of

unknown materials, the following question was asked: "Do you grind up single crystals in

order to use the powder method of identification? If yes, why do you not use the singlecrystal method [check as many as apply]?" Most respondents (132) answered "no", but a significant number (87, or 40%) checked "yes". The reasons given for using the powder method

when single crystals are available are summarized in Table 13.

Table 13. Reasons for Not Using the Single-Crystal Method (II-7)

Number of

Respondents Reason

30 Powder method is easier, faster, routine

28 Too difficult to obtain a good single crystal

25 Do not have the necessary equipment

19 Tradition

14 A trained technician is required

9 Crystal Data is not up to date

6 Too difficult to calculate a unit cell

6 The equipment is too expensive

5 Use a Gandolfi camera instead

4 Too complicated to transform the unit cell

to the Crystal Data cell to get the determinative ratio

2 The PDF file is available for computer search

20 Otherb

The responses occurring more than once under "other" have been

included in the table; the number of times these responses might

have been checked if they had been included in the questionnaire

is unknown, but probably much greater than indicated.

The following reasons were given:

1. Used as standard for powder diffraction.

2. Usually have mixtures, rather than pure substances, for

analysis.

3. We involve all supporting techniques.

4. Different type of data in powder file. Somehow, one has

the feeling that if you fit 20-40 powder lines (both d and

I) it is surer than fitting 6 unit cell dimensions. But we

have been successful using cell constants too.

5. We are usually given powders.

6. If there are several crystals, why not?

7. Educational training.

8. Use single crystal when we can't find diagram in powder

file.

9. Single crystal [equipment] is usually in use by another

individual . 10. To grind up single crystals to powder is useful for "fingerprinting purposes" of complex compounds to compare batches etc,

during syntheses.

11. Generally powder patterns for comparison are more readily

available.

12. Small sample.

13. To reduce size of sample crystallites.

14. We may have a group of crystals expendable.

13
Table 13 (continued)

15. The powder data gives 20 or more pieces of information and

therefore gives normally a completely unique identification.

Lattice constants and their ratios typically do not give a unique identification. Also, data are not as complete.

Many substances have published powder patterns but no lattice

constants.

16. To confirm solid solution etc.

17. Macromolecules rarely yield large single crystals.

18. For comparison of samples not crystallized [microcrystalline], need powder patterns.

19. Too many students and not enough time for equipment

available.

20. The excuses listed above are those of people who are either ill-informed, lazy, or prejudiced.

It can be seen from Table 13 that the powder method is used, rather than the singlecrystal method, primarily because it is easier, faster, and more routine, or because equipment necessary for the single-crystal method is not available. Since the single-crystal

method of identification is a powerful technique, it is hoped that these objections will be overcome. Responses such as numbers 4 and 15 listed under "other" also indicate a need for

education, even among crystal! ographers; the fact that the Crystal Data file is roughly

twice the size of the powder data file and the fact that the unit cell parameters give fewer

possibilities for an unknown than given by comparison of powder data need to be publicized

more.

Since many substances may appear in either the Powder Diffraction File or the Crystal

Data File, but not both, the powder method and the single-crystal method for identification

should be used in a complementary fashion. The following example of this type of use was given in response to question II-5: "Using the JCPDS file, a material was identified as a compound it could not possibly be. The cell constants for that material were used [to calculate] the determinative ratios and Crystal Data consulted for compounds around that

ratio. The correct material was found easily. The pattern for this material did not exist

in the JCPDS file."

2.2.5 Use of Crystal Data Space-Group Tables

The next question concerned the use of Crystal Data Space-Group Tables and Nowacki's

Systematic Tables , in which compounds are grouped according to crystal system and space

group. Question II-8 asked, "Do you use the Crystal Data Space-Group Tables or Nowacki's

Systematic Tables? If yes, briefly describe one or more applications to your work." Most

respondents (150) answered "no". However, 66 (roughly one-third the number of users of

Crystal Data Determinative Tables ) checked "yes", and 38 commented on their use. Again, the

responses were more general than specific; the responses are given in full in Appendix C,

grouped by user categories. An attempt was made to group the responses by area of application, with the results summarized in Table 14.

Table 14. Areas of Application of Crystal Data Space-Group Tables

and Nowacki's Systematic Tables (I 1-8)

Number of

Respondents Area of Application

10 To locate isostructural compounds,

compounds with specific space groups,

or related materials

8 As a research tool; relation of

symmetry to structure

7. To determine or verify space groups

14
Table 14 (continued)

4 As an aid to identification

2 As an aid to teaching

7 Other (used occasionally, or only

for interest)

Although the number of respondents was not large, the areas of application indicated

can be quite useful in materials science. For example, one industrial user responded:

"Compounds with certain space groups were predicted to have properties which we wanted to study. The Space-Group Tables provided a starting point: determining what compounds had

those space groups so that substituted compounds might also be studied." Another respondent

at a government laboratory indicated that the Space-Group Tables were used to "search for

isomorphous compounds of explosive or oxidizer nature so as to make mixed crystals of

same." Areas of research application indicated include group-subgroup relationships,

correlation between chemical class and space group, theoretical relations of symmetry to structure, and use in single-crystal ESR and NMR work.

2.2.6 Suggestions for Improvement of Crystal Data Determinative Tables

The respondents were next asked to conment on ways in which Crystal Data Determinative

Tables could be improved (question II-9). There were 81 responses, and those given two or more times are summarized in Table 15. It is obvious that many users are concerned about

the out-of-date coverage of the inorganic materials, with 30 respondents requesting more

complete coverage, keeping Crystal Data current, or annual updates between editions.

Sixteen respondents commented that they were satisfied with Crystal Data as it is. The

existence of multiple entries for several compounds was conmented on by eight respondents,

with the suggestion that these entries be consolidated, the out-of-date data eliminated, and

the data evaluated so that the best data are indicated.

Table 15. Ways To Improve Crystal Data Determinative Tables (II-9)

Number of

Respondents Comment

30 Keep up to date; more complete coverage;

annual updates between editions.

16 Crystal Data is a good book as it 1s.

8 Consolidate entries; eliminate out-of-date

data; evaluate the entries and indicate

the best data.

4 Add cross-references to other data bases

(Cambridge, JCPDS, Structure Reports, etc.).

3 Include more Information on physical

properties.

3 Include more optical data.

2 Make the data base available for computer

search.

2 Reduce the cost of the books, so that they

may be purchased for personal use.

2 Include data on solid solutions.

2 Add powder data, or references to powder

data.

15
2.2.7 Evaluation of Data Prior to Publication

The next question (11-10) asked, "If a paper submitted for publication contains crystal

data, do you think the data should be evaluated (e.g. checked for inconsistencies) prior to publication as part of the journal review process?" Of the 223 responses to this question,

184 (83%) said "yes", and 39 (17%) answered "no". Several of those who felt this evaluation

should not be done added comments that they were concerned about the time it would take and

the cost.

2.2.8 Assistance to the Crystal Data Project

Finally, the respondents were asked if they would be willing to assist the Crystal Data

project (question 11-11). Most respondents (137) said they would be willing to send in

crystal data directly prior to publication, but a significant number (65) said they would

not. When the respondents were asked if they would be willing to help by abstracting a class of compounds from the published literature or by abstracting crystal data for all

compounds from a given journal, 141 replied "no" and 51 replied "yes". The respondents who

are willing to help with the project (nearly 22% of those returning the questionnaire)

represent a valuable resource for future editions of Crystal Data , as well as indicating the

interest in and value of this compendium.

2.3 Supplementary Content of Crystal Data Entries

In addition to the basic Crystal Data information (unit cell, space group, number of

molecules per unit cell, information on whether or not the structure has been determined,

measured and calculated densities, chemical name and formula, and literature reference), the

respondents were asked to indicate the desirability of including additional data in a typical Crystal Data entry. Question III-l asked for the importance to the user of seven types of information, with the results summarized in Table 16. The rating scale was 3

= high value, 2 = moderate, 1 = marginal, and = no value. As indicated in the table, most

information was checked as being moderately useful, with the source of cell data considered

most valuable. Of particular interest to this study was the lack of confidence in the

Chemical Registry Number as assigned by Chemical Abstracts, which was rated as only marginally important. Two respondents added comments expressing dissatisfaction with the Chemical

Registry Number.

Table 16. Importance of Supplementary Data (III-l)

Number of Average

Respondents Rating^ Item

208 2.5 Source of cell data (single-crystal

or powder work)

204 2.2 An indication that indexed powder

data may be found in the literature

reference

207 2.1 An indication that recorded powder

data may be found in the literature

reference

204 2.1 Cross-reference to the JCPDS

powder data file

203 1.8 Specific method of obtaining

cell data

202 1.6 Refined R-value

191 0.9 Chemical Registry Number

^See definition in Table 7,

16
The next question concerned the importance of supplementary information that has traditionally been included in Crystal Data Determinative Tables . The respondents were asked to indicate if it is useful to have information in the commentary on several data items, with

the results given in Table 17. The data items were rated as being moderately useful to marginally useful, with the same rating scheme as used in question III-l. The two data

items that concern the primary crystal lographic parameters, the existence of sub-, super-,

or pseudocells and the temperature of data taking, were rated as most useful.

Table 17. Rating of Data Items (III-2)

Number of Average

Respondents Ratinga Item

197 2.0 Existence of sub-, super-, or pseudocells

198 2.0 Temperature of data taking

196 1.9 Melting point

200 1.8 Color

192 1.8 Indication of neutron or el diffraction data

194 1.8 Twinning

199 1.7 Habit

199 1.7 Refractive indices

195 1.6 Solid solution studies

202 1.5 Source of polymorphic forms

195 1.5 Cleavage planes

196 1.3 Goniometric axial ratios

193 1.3 Thermal expansion studies

191 1.2 Locality for minerals

192 1.1 Pleochroism

191 1.0 Compressibility studies

^See definition in Table 7.

2.4 Literature Coverage

Two questions were asked concerning the handling of references when more than one paper

has appeared containing cell constants for a given material. Question IV-1 stated, "Many

publications containing unit-cell dimensions do not give new cell or structural data, but

may provide additional crystal lographic information such as an indexed powder pattern, solid

solution data, thermal expansion data, or cell data for a mineral of slightly variant com- position. References of this type should be treated as follows [check one]". The responses

checked are given in Table 18. The majority of respondents answering this question (145, or

69%) checked that these papers should be given only as a reference with an indication of the

type of information to be found, while 43 (20%) felt that they should be reported in full,

including unit-cell dimensions.

17
Table 18. Treatment of Multiple References to a Given Material (IV-1)

Number of

Respondents Response Checked

145 Given only as a reference with an indication of the type of information

to be found in the paper

43 Reported in full, including unit-cell

data

15 Given only as a reference

6 Omitted from Crystal Data

2 Other^

^Significant new data may be a useful criterion; the underlined data

[powder pattern] I would expect to find in the JCPDS Powder Diffraction

File.

The next question (IV-2) asked if, to facilitate data handling, it would be acceptable

to publish annotated references of the above type as a supplement to Crystal Data , with

appropriate indexes. This format was checked as being acceptable by 145 respondents, while

41 checked that this would not be desirable.

2.5 NBS Crystal Data Center Published Products

The respondents were asked to rate potential Crystal Data products based on importance

to their work, using the scale 3 = high value, 2 = moderate, 1 = marginal, = no value.

The results are summarized in Table 19.

Question V-1 concerned Crystal Data Determinative Tables . The publication of a supplement to the inorganic section for 1970-1978 was rated at high to moderate value, with 114

respondents (59%) indicating this would be of high value to their work. This result is in

agreement with the response to question II-9, and underlines the importance of bringing

Crystal Data up to date. The publication of a cumulative name and formula index for the

inorganic volumes was rated as being of moderate value, with one respondent commenting that

"a cumulative index begins to be of value if more than two volumes are covered".

The respondents were asked to give the value of bringing Crystal Data up to date more rapidly for certain categories (question V-2). Only the category of refined inorganic

quantitative structures was rated as of moderate value, with the special publication of

Crystal Data for minerals, metals and intermetallics, or oxides only rated as of marginal to moderate value. Since these publications would be of interest to smaller groups of users,

this reply is to be expected. The following numbers of respondents felt that these separate

publications would be of high value: refined inorganic quantitative structures, 76 (41%);

minerals, 68 (36%); oxides, 40 (22%); metals and intermetallics, 35 (20%). Two respondents

expressed concern about these special publications. One commented, "I disapprove in principle of this kind of approach. If you give a person a book with data on minerals only, he or

she will implicitly assume that everything to be sought can be found in it and that isn't

true"

.

The publication of the Identification Tables (question V-3) was rated as being of

slightly greater than moderate value, with 79 respondents (41%) rating it as of high value

to their work and 58 (30%) as of moderate value. The response indicates that this could be

a valuable new publication.

Finally, a second issue of Crystal Data Space-Group Tables (question V-4) was rated as being only of marginal, to. moderate value, with 22 respondents (12%) rating it as. being of

high value. This result is in agreement with the lack of general use indicated in question

II-8.

18
Table 19. NBS Crystal Data Center Published Products (V-1. V-2. V-3. V-4)

Number of Average

Respondents Rating^ Product

V-1. Crystal Data Determinative Tables

192 2.4 A supplement to the inorganic section

of Crystal Data covering the literature

for 1970-1978"

188 2.0 A cumulative name and formula index for

the 3rd Edition of Crystal Data for Volume 2 (inorganic literature through 1966) and

Volume 4 (inorganic literature 1967-1969)

V-2. Crystal Data for special categories

187 2.0 Crystal Data for refined inorganic quantitative structures only (1970-1978)

188 1.7 Crystal Data for minerals only (1970-1978)

178 1.5 Crystal Data for oxides only (1970-1978)

178 1.3 Crystal Data for metals and intermetallics

only (1970-1978)

40 Other^

V-3. Crystal lochemical Identification Tables

192 2.1 This is a new product designed for the

rapid identification of unknown materials.

For a given compound, an entry would consist of one line of key crystal lographic

and chemical data (reduced cell, space

group, formula, density, and literature

reference). Data from all volumes of

Crystal Data would be included.

V-4. Crystal Data Space-Group Tables

178 1.4 A second issue of Crystal Data Space-Group

Tables including data coincident with

Volume 3 (organic) and Volume 4 (inorganic)

of Crystal Data Determinative Tables . The

first issue (J. Phys . Chem . Reference Data , 6^, 675, 1977) is coincident with Volumes

1 and 2 of the 3rd Edition of Crystal Data .

^See definition in Table 7.

Organics and organometallics (17), sulfides (5), proteins

and biological macromolecules (4), fluorides (2), zeolites

(2), phosphates (2), silicates, pharmaceutical biochemicals,

sulfates, semiconductors, hydroxides, halides, polymers,

explosives

19
2.6 Crystal Data File Searches and Analyses

This section concerned computer-based methods of dissemination and use of the Crystal

Data file. The increased use of computer search techniques can be seen in the responses

given. As one user commented, "the size of Crystal Data makes computer methods imperative."

2.6.1 Computer-Based Methods of Dissemination

Questions VI-1 and VI -2 asked the respondents to compare three potential methods for

computer search of the data base:

Method A . On-line Interactive Search System

The Crystal Data file will soon be available to the public as a component of CIS

(Chemical Information System of NIH/EPA). This system is an on-line interactive

search system; the user queries the file via a terminal and receives an answer in

a yery short time. For example, one could find all compounds with a given cell,

space group, or formula within a few minutes.

Method B . Batch Search System at Central Location

Such a system would be operated at a central location with a resident crystal lographic expert to interface between the user's query and the batch-operated com- puter system. Questions would be received and answered via mail or telephone.

Several days might be required for the process.

Method C . User's Organization to Buy Computer Data Base

In this system the organization would pay for the data base, appropriate software,

and yearly updates. The organization and the users would then decide on the most

appropriate way to use the file.

The large size of the Crystal Data file makes computer searches a valuable asset. In question VI-1, the respondents were asked to indicate how important such a search ability

would be in their work for methods A, B, and C [3 = high value, 2 = moderate, 1 = marginal,

= no value], and to indicate the maximum acceptable cost if possible. The results are summarized in Table 20. It can be seen that method A was preferred by most users, with 64

respondents (33%) rating the on-line interactive search method as being of high value, and

60 (31%) as of moderate value in their work. For method B (batch search system at a central

location), 21 respondents (11%) indicated high value and 44 (24%) indicated moderate value;

for method C (user's organization to buy computer data base) 25 respondents (15%) indicated

high value and 26 (15%) indicated moderate value.

Table 20. Methods of Computer File Search (VI-1)

Method

Number of

Respondents

Average

Rating^

Number of

Respondents Median Cost

A 194 1.8 82 $10 per query

B 184 1.2 47 $10 per query

C 168 1.0 29 $500 for file

^See definition in Table 7.

Many fewer respondents attempted to estimate the maximum acceptable cost for the file

search or purchase. For method A, the cost per query ranged from $1 to $500, with a median

of $10, and for method B the cost per query ranged from $1 to $100 with a median of $10.

Only 29 respondents attempted to estimate the acceptable cost for purchase of the file

(method C); the values given ranged from 'free' (s4nce funded through government sources) to

20
$3000, with a median of $500.

In question VI-2 the respondents were asked to comment on the relative merits of the

above approaches (A, B, C) with respect to their needs. Aqain, the on-line interactive

search system (method A) was preferred by 52 respondents (48% of those commenting); method B was preferred by 20 (19%), and method C was preferred by 18 respondents (17%). A manual

search through the book was felt to be adequate by 11 respondents, 4 respondents commented

that computer searches would be too costly, and 3 respondents remarked that the preferred

method would depend on the frequency of use and local computer facilities. The advantages

and disadvantages of the three methods given in the comments are summarized in Table 21.

Table 21. Relative Merits of Computer Search Methods (VI-2)

Method Advantages Disadvantages

A Best and cheapest for Needs support to continue;

intermittent use; problems with proprietary

easiest to use; many information

users are already using

CIS

B Best when individual May be too expensive; no use is low; allows immediate answer; problems

guidance for new users; with proprietary information

do not need computer

access

C Best for frequent use Too expensive to implement

or large group of users; and maintain; need staff

necessary for propri- member to oversee project

etary information

It can be seen from Table 21 that the advantages of the three methods depend largely on the frequency of use. The batch search (method B) would be preferred for low use, the online search (method A) would be preferred for occasional or intermittent use, and the inhouse data base (method C) would be best for frequent use or for a large group of users.

The public nature of the file access procedures for methods A and B might be a problem for

queries concerning proprietary information.

2.6.2 Research Using a Computer Data File

Finally, the last question (VI-3) asked, "Assume that the Crystal Data file, software,

and computer time are all availatDle at a centrally supported site. If funding were available to support you for one month to one year, would you consider doing research taking

advantage of the data in the file?" Nearly one-half of the 176 respondents to this question

(85, 48%) answered "yes". This represents a potentially large and unexplored research

resource. As one respondent commented, "this is an essential ingredient in promoting use of

the file."

3.0 Summary of Results and Conclusions

The questionnaire on Crystal Data was distributed in December of 1978 and January of

1979 by the NBS Associateship of the JCPDS. A total of 235 responses were received from

representatives of industry (37%), universities and colleges (43%), and government (16%).

Most respondents characterized their work as basic and/or applied research, and used both

powder diffraction and x-ray single-crystal diffraction in their work.

The overall frequency of use indicated for Crystal Data Determinative Tables was high,

with 81% of the respondents reporting occasional or frequent use in more than one category.

The major area of application was in crystal structure analysis (143 responses), with significant use in phase equilibria (53), materials processing (42), high or low temperature

studies (40), corrosion (33), and catalysis (29). The types of materials most freauently

checked were ceramics (51) and semiconductors (29), although magnetic materials, optical

21
materials, and energy conversion materials were also important.

Specific examples of the use of Crystal Data could be grouped into the following areas

of application: materials analysis and qualitative identification; aid in research applications; to assign structure type or search for isostructural materials; for literature search

or location of cell parameters; to find out if a structure has been determined; as an aid in

teaching and design of experiments. Examples of use given in the area of materials analysis

included identification of unknown compounds in a phosphoric acid plant, refractories, and

human tissue. Research applications mainly involved use of the structural relationships

found in Crystal Data for the design of materials with given properties, and extended to such diverse areas as theoretical calculations, bonding electron distribution studies,

interpretation of radial distribution functions and extended x-ray absorption fine structure,

correlation of polytypes with luminescence, and calculation of theoretical powder patterns.

Several examples were also given in which a crystal structure could be assigned through the

location of isostructural materials.

The usage of Crystal Data directly for the identification of unknowns is lower than the

use of the powder method; the powder method was preferred primarily because it is easier,

faster, and more routine, or because equipment necessary for the single-crystal method is

not available in the respondent's laboratory. This indicates (1) that the development of a rapid and inexpensive method for unit-cell determination would be desirable, and (2) that

there is a need for education of the scientific community, as the single-crystal method of

identification is in many cases more powerful than the powder method owing to the uniqueness

of the unit cell and the larger size of the Crystal Data file (^-60,000 entries ys_. '\'32,000

in the Powder Diffraction File).

Crystal Data Space-Group Tables or Nowacki 's Systematic Tables were used by roughly

one-third the number of users of Crystal Data Determinative Tables . Examples of use in the area of materials design included location of materials in a given space group to study

properties related to that space group, and location of isomorphous substances so as to make

mixed crystals with desired properties. Research applications included group-subgroup

relationships, correlation between chemical class and space group, theoretical relations of

symmetry to structure, and use in single-crystal ESR and NMR work.

The value of the inclusion of various supplementary data items was rated by the respondents, and these ratings will be considered for future data input. Also, several data items

previously abstracted, such as goniometric axial ratios and compressibility Information, were rated as relatively unimportant, and these may be deleted.

The most frequent suggestion for improvement was that the coverage should be more complete, or annual updates be published between editions; the necessity for complete coverage

was further indicated by the fact that over one-fourth of the respondents reported that they

had needlessly duplicated crystal structure determinations at a median cost of $2000. It was also suggested that entries be consolidated; most respondents felt that duplicate

references to the same material should be given only as a reference with an indication of

the type of information to be found, and indicated that it would be acceptable to publish

annotated references of this type as a supplement to Crystal Data . The development of the

computer-based data file currently being implemented should make 1t possible to overcome

these deficiencies, particularly if a suitable data base management system is included.

Adequate computer typesetting capability is also required.

The respondents also indicated a willingness to help with the Crystal Data project.

Most said that they would be willing to send in data directly prior to publication, and 51 respondents indicated that they would be willing to help with abstracting; this represents a valuable resource for future Crystal Data publications and indicates the interest in and

value of this compilation. The expansion of funding for abstracters is thus desirable; this

would help to alleviate the problem of out-of-date coverage.

Potential published products rated as of moderate to high value by the respondents were

the following:

(1) A supplement to the inorganic section of Crystal Data covering the literature

22
for 1970-1978. The publication of this supplement was given as most important, again indicating the need for complete coverage.

(2) The Crystal lochemical Identification Tables with key crystallographic and

chemical information for all compounds in the Determinative Tables. This new product is

ready for typesetting, and should be made available soon for identification of unknowns both

as a printed version and a computer file for automated search.

(3) A cumulative name and formula index. The feasibility of such a publication is

currently being assessed.

(4) Crystal Data for refined quantitative inorganic structures (1970-1978). This

product would help eliminate duplication of crystal structure determinations. Other subfiles (minerals, metals and intermetallics, oxides) were rated as of high value to smaller

groups of users, as would be expected.

The preferred method of computer-based dissemination of the Crystal Data file was an on-line interactive search technique, particularly for moderate or intermittent use. A subfile of Crystal Data is currently being tested for distribution on the Chemical Information System (CIS) network. A batch search at a central location was felt to be desirable

for low usage or those without computer access, and an in-house data file and search capability was preferred for frequent use or for a large group of users. All three methods of

dissemination appear to be valuable to various groups of users; also, great interest was indicated in the possibility of doing research taking advantage of a computer-based Crystal

Data file. It is proposed that the file be made available at NBS for on-line search, for

batch search with NBS acting as a regional data center, and for research using the file.

23
APPENDIX A

QUESTIONNAIRE ON CRYSTAL DATA

[The number of responses has been added for each item.]

I. Description of Respondent

1. Your present type of work [check as many as appropriate]:

168 D Basic research 19 n Quality control

104 n Applied research 62 n Analysis

29 n Product development 78 n Education

13 D Production 1 n Student

7 D Other (please specify)

2. Employer:

86 n Industrial 102 c University or college

37 n Government 11 n Research institute

5 D Other (please specify)

3. Please check one or more of the following Standard Industrial Classifications

which best describe your employer:

5 D 10 Metal mining

2 G 11 Anthracite mining

7 D 12 Bituminous coal and lignite mining

5 D 13 Oil and gas extraction

8 D 14 Mining of nonmetallic minerals, except fuels

51 n 28 Chemicals and allied products

6 n 29 Petroleum refining

16 n 32 Stone, clay, glass, and concrete products

8 n 33 Primary metal industries

13 d 34 Fabricated metal products

4 n 35 Machinery, except electrical

18 D 36 Electrical and electronic equipment

5 D 38 Instruments and related products

12 D 80 Health services

1 n 81 Legal services

97 D 82 Educational services

24
3 D 84 Museums, art galleries, botanical and zoological gardens

3 D 91 Executive, legislative, and general government

1 n 92 Justice, public order, and safety

6 D 95 Environmental quality and housing

12 n 97 National security and international affairs

43 n Other [please describe]

4. In your work do you use [check as many as appropriate]:

189 D X-ray powder diffraction 167 n X-ray single-crystal diffraction

21 n Neutron diffraction 44 n Electron diffraction

5. Please check one or more of the types of materials routinely involved in your

work:

177 D Inorganics 73 n Ceramics

67 D Metals and intermetallics 64 n Small molecules

118 n Minerals 21 n Large molecules or proteins

51 n Catalysts 13 n Pesticides and herbicides

81 D Organics 29 n Drugs

59 n Organometallics 14 n Other (please specify)

6. Name and address of present employer [optional]:

177

7. Your name, address, and telephone number [optional];

169

II. Use of Crystal Data

1. How often do you use Crystal Data Determinative Tables in the following ways [use

3 = frequently, 2 = occasionally, 1 = rarely, = not at all]:

3 / 2 23/54 To identify an unknown substance using the determinative ratio

58/77 To find out if the structure of a particular substance has been determined

35/81 To find information about structure types or to locate isostructural materials

62/81 To find cell dimensions or space group of a particular substance

25
9/48 To obtain information about physical properties (e.g. color, habit, mp) of

a substance

30/74 To locate literature references containing crystal data on a particular

substance or structural group (e.g., phosphates, cyanates, etc.)

17 Other (please specify)

Do you use Crystal Data in one or more of the following areas [check as many as apply]:

143 n crystal structure analysis

42 n materials processing

33 D corrosion

16 n diffusion in metals

53 D phase equilibria

11 D failure prevention

17 n fracture or wear studies

10 n materials durability

29 n catalysis

23 D magnetic materials

20 n energy conversion materials

29 n semiconductor materials

51 n ceramic materials

23 n optical materials

17 n high pressure studies

40 n high or low temperature studies

Have you ever solved a structure or collected data and then found that your work

was unnecessary because the same or similar substance had already been solved?

159 D No

64 n Yes. If yes, how often has this happened? What is your dollar estimate of

the cost involved (computer time, lost hours, etc.) for each occurrence?

59

Have you ever determined cell parameters for a compound or group of compounds and

then discovered that your work was a duplication of previously published data?

158 n No

63 n Yes. If yes, how often has this happened? What is your dollar estimate of

the cost involved for each occurrence?

55

Please describe one or more specific applications of Crystal Data Determinative

Tables, showing the type of information needed and how it was used.

106

26
6. Do you need to identify unknown crystalline substances in your work?

30 n No

200 n Yes. If yes, do you rely mainly on the powder method (ASTM-JCPDS file) or

the single-crystal method [check one]:

60 n Use powder method exclusively

105 n Use mostly pov/der method but also use Crystal Data for confirmation or for literature references

46 n Use primarily single-crystal method

7. Do you grind up single crystals in order to use the powder method of identification?

132 n No

87 D Yes. If yes, why do you not use the single-crystal method [check as many as apply]:

6 D Too difficult to calculate a unit cell

25 n Do not have the necessary equipment

6 n The equipment is too expensive

14 n A trained technician is required

28 D Too difficult to obtain a good single crystal

4 n Too complicated to transform the unit cell to the Crystal Data cell to get the determinative ratio

9 D Crystal Data is not up-to-date

19 n Tradition

57 D Other (specify)

Do you use the Crystal Data Space-Group Tables or Nowacki's Systematic Tables?

150 D No

66 n Yes. If yes, briefly describe one or more applications to your work

38

In what ways could Crystal Data Determinative Tables be improved to serve you?

Please give us your comments.

81

27
10. If a paper submitted for publication contains crystal data, do you think the data

should be evaluated (e.g. checked for inconsistencies) prior to publication as part of the journal editorial review process?

184 n Yes 39 n No

11. Would you be willing to assist the Crystal Data project:

By sending us your crystal data directly prior to publication?

137 D Yes 65 n No By abstracting a class of compounds from the published literature or by abstracting

crystal data for all compounds from a given journal?

51 D Yes 141 n No

III. Supplementary Content of Crystal Data Entries

1. Indicate the importance to you of the following types of information that might be

found in a given Crystal Data entry [use 3 = high value, 2 = moderate, 1 = marginal , = no value]:

3 / 2 135/50 Source of cell data (single-crystal or powder work)

53/74 Specific method of obtaining cell data (e.g., "refined on 30 reflections

from single-crystal diffractometer data").

86/75 An indication that recorded powder data may be found in the literature

reference

85/81 An indication that indexed powder data may be found in the literature

reference

85/61 Cross-reference to the JCPDS powder data file

13/36 Chemical registry number

43/63 Refined R-value (for quantitative structures)

2. In order to speed up processing and obtain an up-to-date file as soon as possible,

we are considering the simplification or elimination of certain data items.

Please indicate if it is useful to have information in the commentary on the

following [use 3 = high value, 2 = moderate, 1 = marginal, = no value]:

3/2 3/2

32/47 Goniometric axial ratios 58/72 Color

50/67 Indication of neutron or 61/49 Refractive indices

electron diffraction data

66/80 Existence of sub-, super-, 21/40 Pleochroism

or pseudo-cells

31/91 Habit 59/67 Melting point

29/69 Cleavage planes 43/62 Solid solution studies

44/77 Twinning 24/51 Thermal expansion studies

69/68 Temperature of data taking 12/36 Compressibility studies

36/29 Locality for minerals 46/59 Source of polymorphic forms

28
IV. Literature Coverage

1. Many publications containing unit-cell dimensions do not give new cell or structural data, but may provide additional crystal lographic information such as an indexed powder pattern, solid solution data, thermal expansion data, or cell data

for a mineral of slightly variant composition.

References of this type should be treated as follows [check one]:

43 D Reported in full, including unit-cell data

145 n Given only as a reference with an indication of the type of information to be

found in the paper

15 D Given only as a reference

6 D Omitted from Crystal Data

2 D Other (please specify)

2. To facilitate data handling, annotated references of the above type could be published as a supplement to Crystal Data, with appropriate indexes.

This format would be 145 acceptable 41_ not desirable

V. NBS Crystal Data Center Published Products

For each of the following published products, please indicate how important the given

product would be in your work [use 3 = high value, 2 = moderate, 1 = marginal, = no value]:

1. Crystal Data Determinative Tables [Indicate importance 3, 2, 1, 0]:

3/2

114/48 A supplement to the inorganic section of Crystal Data covering the literature for 1970-1978 ('\>20,000 entries)

65/67 A cumulative name and formula index for the 3rd Edition of Crystal Data

for Volumes 2 (inorganic literature through 1966) and 4 (inorganic literature 1967-1969).

2. Crystal Data for special categories (these may be brought up to date more rapidly)

[Indicate importance 3, 2, 1, 0]:

3 / 2 68/33 Crystal Data for minerals only (1970-1978)

35/27 Crystal Data for metals and intermetallics only (1970-1978)

76/47 Crystal Data for refined inorganic quantitative structure only (1970-1978)

40/44 Crystal Data for oxides only (1970-1978)

40 Crystal Data for other classes (please specify)

3. Crystallochemical Identification Tables [Indicate importance 3, 2, 1, 0]:

3 / 2 79/58 This is a new product designed for the rapid identification of unknown

materials. For a given compound, an entry would consist of one line of key

29
crystallographic and chemical data (reduced cell, space group, formula,

density, and literature reference). Data from all volumes of Crystal Data

would be included.

4. Crystal Data Space-Group Tables [Indicate importance 3, 2, 1, 0]:

3/2

22/56 A second issue of Crystal Data Space-Group Tables including data coincident

with Volume 3 (organic) and Volume 4 (inorganic) of the Crystal Data

Determinative Tables. The first issue (J^. Phys. Chem. Reference Data , 6^, 675, 1977) is coincident with Volumes 1 and 2 of the 3rd Edition of Crystal

Data

.

VI. Crystal Data File Searches and Analyses

1. The large size of the Crystal Data file makes computer searches a valuable asset.

For the following methods, please indicate how important such a search ability

would be in your work [use 3 = high value, 2 = moderate, 1 = marginal, = no value]. If possible, also indicate the maxmium acceptable cost.

A. On-line Interactive Search System

3/2

64/60 The Crystal Data file will soon be available to the public as a component of CIS (Chemical Information System of NIH/EPA). This

system is an on-line interactive search system; the user queries the

file via a terminal and receives an answer in a very short time. For example, one could find all compounds with a given cell, space group,

or formula within a few minutes.

$ 10 Maximum cost per query (median of 82 responses)

B. Batch Search System at Central Location

3 / 2 21/44 Such a system would be operated at a central location with a resident

crystallographic expert to interface between the user's query and the

batch-operated computer system. Questions would be received and

answered via mail or telephone. Several days might be required for

the process.

$ 10 Maximum cost per query (median of 47 responses)

C. User's Organization to Buy Computer Data Base

3 / 2 25/26 In this system the organization would pay for the data base, appropriate software, and yearly updates. The organization and the users would then decide the most appropriate way to use the file.

$500 Maximum cost for file (median of 29 responses)

2. Please comment on the relative merits of the above approaches (A, B, C) with

respect to your needs 52A 20B 18C .

3. Assume that the Crystal Data file, software, and computer time are all available

at a centrally supported site. If funding were available to support you for one month to one year, would you consider doing research taking advantage of the data

in the file?

85 D Yes 91 n No

30
APPENDIX B

SPECIFIC AREAS OF APPLICATION OF CRYSTAL DATA DETERMINATIVE TABLES (II-5)

INDUSTRIAL

A search for a number of isotropic substances was desired. Searching in the cubic

section was most useful, yielding many compounds which fit our particular needs.

Can often index a powder pattern as cubic quickly with a slide rule (B/D scale method

with inverted slide) then check in Crystal Data for possible or isomorphous compounds

with the same or similar unit cell.

o A small (approximately lOOOA) crystallite was isolated in a piece of human tissue. The

crystal provided an electron diffraction pattern. Only elemental information and twodimensional diffraction data [were available]. The crystallite was identified with the

aid of Crystal Data.

We use our x-ray diffraction mainly to identify reaction compounds which form in refractories while they are in use. The data is used to suggest refractories which might

provide better service in such applications, or it may aid in the development of

improvements in the refractory products.

In attempting to prepare analog structures use Crystal Data as a source as to what has

been reported. Example: eulytite, Bi4Si30i2 - check how many A and B site substitutions are known. Same use for other mineral analogs.

Searched for all compounds crystallizing with a given a and b^ dimension (indeterminate)

and a given angle between a_ and b^ for use in layer stac1<ing studies.

We have been interested in certain cubic, hexagonal, and orthorhombic space groups and

have used the Crystal Data Determinative Tables as a source of materials crystallizing

in the desired space groups.

Searching for isostructural materials to aid in identification. The structure type

is recognized, lattice parameter(s) determined, and lattice constant or ratio used to search for compound possibility - usually elemental data is also available to aid in

the search.

Crystal Data is used exclusively for identification of multiphase samples. The Tables

are used to determine semi-quantitative mineralogical analyses by process of elimination of diffraction peaks published by JCPDS.

If the electron diffraction data and the card file match disagree, the Determinative

Tables usually give us the isomorph.

1. Identification of fillers in polymer products.

2. Determination of crystallinity and orientation in polymers.

3. Identification of corrosion products on plated copper conductor.

4. Determination of d_-spacing in carbon blacks.

Look for oxides having spinel structure and having lattice parameter within a certain

range. These spinels would be possible substrates for epitaxial growth of other compounds.

I have had several problems involving an unknown substance mixed with kaolin. I have

solved these problems by the Determinative Tables.

Identifying inorganic components in a polymer composite.

[Used for identification] without the aid of chemical data when d_-spacings are close

together.

31
16. We use both Crystal Data and Pearson's handbook of metals and alloys as a backup reference source to our PDF file. These books cut down the volume of literature searching

which might otherwise have been done for research projects. We usually do not use them

for identifying unknowns.

17. Identification of corrosion products.

18. To identify structurally isomorphous materials of a particular structure type.

19. In addition to the uses in II-l, have indexed an unknown powder pattern with known

chemistry and looked up the axial ratio to see if the structure was known or discovered.

20. 1. Axial ratio was used to find alloy analog of (Tlo.75Pbo.75)ifCl5 viz ZrsSiij prior

to determining structure.

2. Everyday use is for getting references and unit cell data.

21. a. Identification of elements by x-ray diffraction identification of ashed residues.

b. Analysis of commercial products.

c. Fingerprinting of compounds.

22. Calculation of a theoretical [powder] pattern for a simple compound (cubic, orthorhombic, tetragonal, or hexagonal) not found in the JCPDS-ASTM file. Information needed:

unit cell parameters, angles, and space group.

23. Practically all my work involves comparisons of lattice constants among isostructural

compounds, such as the spinel structure, the KH2P0it structure, etc. Therefore, the important thing is the completeness of coverage of different compounds within the structure type, as is evaluation of the data (i.e. inclusion of poor data where better data

are available is not useful).

24. 1. Once obtaining lattice and space group of an unknown, (a) search to make sure structure not already solved; (b) see if there are analogous structures.

2. To generate powder diagrams via computer using crystal lographic data.

25. To find any similar compounds or related structures during new mineral description.

26. In some cases cell constants and space groups are given for a material cited in the PDF which are not indexed on the PDF card. This saves a lot of trouble trying to index

that material. Often, cell data from a number of investigations are cited for a single

substance. One doesn't always get these cross references from the PDF file.

27. My most frequent use of the Tables is to find whether the structure of particular substances has been done. In this context, the formula index is the first most useful

part of the book.

28. Identification of different minerals in ore or separation of caustive [sic] agents in

unit operations.

29. When a sample is identified as having elements that could not be present, Crystal Data

is used to find isostructural compound that could be possible.

30. Identification. of crystals based on ratios of a_ to b^ to £ (unit cell dimensions).

31. Identification of phases.

32. Identify unknown powder patterns.

33. Generally used to check out identification of unknown single crystals.

34. Mainly used for identification of compounds not in the JCPDS file.

35. Data on unit cells of KMnOi^ and KCIO4 was consulted to develop a teaching experiment on solid solutions of these two salts.

32
1. Adduct - cell dimensions. Other proprietary [compounds] also [identified by] unit cell

dimensions.

'. Identifying simple crystals present in a mixture.

I. Having a unit cell, I would use the Tables to see if the structure could be easily

guessed by comparing it to known compounds. Used many times for a quick reference

check.

39. Checking for unknown. Checking for oxygen states.

40. By use of unit cell ratio or cell size, have located a material for identification of

an unknown.

41. To determine that a crystalline precipitate was CrOa from the axial ratios.

42. Mostly powder work. Clarification of some powder data or if powder data is not available. For references. To help in solid solution evaluation.

U NIVERSITY or COLLEGE

Local phosphoric acid plant was having trouble with an unknown compound precipitating

in pumps and pipes. Was able to identify compound and advise on how to manage settling

ponds to avoid problem.

We made a high pressure run in an attempt to prepare a specific new compound. An x-ray

powder photograph of the result showed that a reaction had occurred and that none of

the original material was present. The starting elements were Nb and Te. The powder

photograph showed a cubic material with a = 4.38 to 4.40A. A quick look through Crystal Data revealed that the "new" material was almost certainly NbN (with N from BN in reaction chamber).

We use crystal lographic data to help interpret radial distribution functions and ex- tended x-ray absorption fine structure data from amorphous materials. Our work is

aimed at determining atomic arrangements in amorphous materials.

Enclosed are reprints of two papers in which references to Crystal Data play an important part. The paper on formates shows some of the shortcomings of Crystal Data [inconsistent data on rare-earth formates in Crystal Data was the impetus for further

structural work], and the paper on the F51 type shows how much information can be

gleaned from Crystal Data [various structure types reported were explained on the basis

of information given in Crystal Data]. Much more work of this sort could be based on Crystal Data.

1. Educational purpose: to find a compound suitable for basic training of students

in course work.

2. To find possible isostructural or related compounds pertaining to current research.

3. Many of my colleagues use the Tables, which I keep accessible to them in my office.

4. There is such a large variety of occasions where the Tables come in handy, I cannot list them all

.

6. Usually used as a screen before starting a structure determination on a given material.

7. A new mineral, maricite, NaFePOi*, had its structure determined by careful checking

against axial ratios and cell dimensions of similar compounds.

To determine if a cubic organomercury compound had been reported. Found that cell edge

and space group were identical to that of Ba(N03)2. Powder patterns proved to be practically identical. These data were used to determine the most probable arrangement of

the ligands in the unknown.

33
9. 1. Use of ratio to identify unknown in standard way.

2. Use of ratio and chemical formulas in Tables to look for potentially isomorphous

materials as a guide to structure of an unknown.

10. [For work on] bonding electron distribution, need fairly simple structures having no peculiarities (disorder etc.) and only moderate symmetry (monoclinic, orthorhombic)

.

Search Crystal Data for likely candidates.

11. My books are frequently borrowed by the theoretical chemists who use the distance and

angle determinations.

12. A "new" mineral was very rare and only the axial ratios were obtained (besides color

and habit). No composition was known. The one crystal measured was tinyl Crystal

Data identified it for me.

13. We routinely examine the Tables every time we analyze a crystal to see if isostructural

(or identical) compounds are known. The Tables serve as an analytical tool.

14. Comparisons of forms of Se. Searched for information on chalcogenide halides, metal

complexes of organic acids (and the organic acids).

15. We have often determined cell constants and space groups of complexes which we have

synthesized and used Crystal Data as an analytical device, i.e., if we suspect that we

know what the complex might be the cell constants are yery useful. The information

needed is simply space group, cell constants, and density.

16. 1. A terpene, trigonal, P3i21 - impossible space group for the compound. Found a compound with roughly the same axial ratio in Crystal Data, which was P3i twinnedsolved the problem (but not the structurel).

2. Mineral names [used to get] formulas (must be geological tables which do this more efficiently, but Crystal Data is handy on my office bookshelf).

17. Description of unit cell transformation for the reduced cell in relation to the original

literature work is yery often helpful, particularly in the triclinic system in relation

to handling of single crystal diffraction films.

18. Mainly used to look up space group and cell dimensions to see if a crystal structure

has been done.

19. Checking variation of cell dimensions and symmetry with composition. Checking unknowns.

20. Checking new structure of unknown substance to see if ratios were similar to known

listed one.

21. Used to find cell constants for all nitrates studied.

22. 1. Easiest access to structure literature.

2. Used in instruction for determinative mineralogy (mostly for cubic).

3. Use Nowacki tables for lectures on relation of symmetry to structure.

23. Currently attempting to prepare unusual metal complexes containing I, TCNQ, or TCNE.

A check of unit cell dimensions on crystals obtained provides information on whether we

have indeed prepared something new.

24. A reference book for problem solving in x-ray crystallography class.

25. Used in surveying references of compounds similar to one whose structure determination

we are carrying out.

26. Mostly to find unit cell and space group of compounds similar to those being studied by

single crystal methods in our own lab. Also for identification of unknowns (powder

data) in teaching instrumental analysis.

34
27. See II-l, items 2, 3, and 4.

28. To find out if a structure was known - most recently that of alanine. Crystal Data,

although not up to date of course, is a quick and easy reference work to use for this

purpose.

29. I have only used the Tables to see if our new crystals of human hemoglobin might be

isomorphous with hemoglobin crystals from other species.

30. In experimental mineralogy, to determine what compounds have been described previously.

31. Axial ratios of knowns to suggest structure type of unknown.

32. Comparison of Crystal Data values with own experimental values (material analysis).

33. In teaching crystallography.

34. How many crystal forms of L-tartaric acid are known? From formula index to Tables for

unit cell data.

35. Identification. Determination of known structures. Literature search.

36. Setting up a powder diffraction experiment for undergraduate lab, I searched for cubic

F cells with similar cell dimensions.

37. Occasionally we identify very small mineral samples by single crystal x-ray oscillation

photos. Also a source book.

38. Needed cell parameters to check against my determined values.

39. Used primarily as a way to identify unknowns (minerals). Quick reference for properties.

40. There must be a computer readable data base of cell parameters, volume, etc. for instant

access. This has been needed for years.

41

.

See II-l on page 2.

42. As already indicated in II-l.

43. Only seek molecular structure information.

44. To identify simple crystals present in a mixture.

GOVERNMENT and NATIONAL LABORATORIES

1. 1. It was suspected that hexagonal (NHit)2SiFe (bararite) was present in a sample, but

no pattern was listed in the JCPDS Powder Diffraction File. Unit cell data from

Crystal Data were used to calculate a pattern.

2. Unit cell data for minerals are sometimes calculated from powder diffraction data,

then compared with values for synthetic materials from Crystal Data to estimate

substitutions. Useful for work with solid solution series.

2. Identification of new superconducting materials - binary and ternary intermetallics.

3. X-ray data for polycrystalline SiC doped with boron were correlated with the lumi- nescence (different polytypes have different emission spectra).

4. We have used Crystal Data to search the literature for information on cell constants

for KBr, which we have adopted as a wavelength calibration standard for our neutron

beams of the High Flux Beam Reactor. Also to locate data on metals, for comparison

with M-M bond lengths obtained in work on metal cluster compounds. Generally use inorganic index most frequently.

35
5. Search of isomorphous compounds of explosive or oxidizer nature so as to make mixed

crystals of same.

6. EuiiAsio was found to be orthorhombic, a»! b; traced to related tetragonal SmnGeio.

EusAsi^, orthorhombic, was traced to related SmsGeit which is not isostructural

7. 1. Quick location of cell constants and space group.

2. Quick check of potential structure types for a specific compound.

3. Check if there are several crystalline forms (types) of a particular compound.

4. In one case, identification of unknown compound made in small quantities when preparing another compound.

8. Salt crystals [were obtained] in a protein crystallization; cell constants determined

only for identification.

9. Crystal Data tables are used to search for a structural and/or chemical analog of a particular new mineral which is too fine grained for single crystal analysis.

10. Lattice constants to provide clues for identification. Chemical formulas to identify

if material has been worked on.

11. Using the JCPDS file, a material was identified as a compound it could not possibly be.

The cell constants for that material were used [to calculate] the determinative ratios

and Crystal Data consulted for compounds around that ratio. The correct material was found easily. The pattern for this material did not exist in the JCPDS file.

12. See enclosed reprint (copy is enclosed, with the paragraph of interest circled). [The

crystal structure of a mineral was solved by finding a known structure with similar

axial ratios, and using this structure as a trial structure for the unknown structure.]

13. Data on zeolites and related alkali and alkaline earth alumino-silicate hydrates - also

Si02 and silica hydrates - sundry mineral group relations. Synthetic inorganic mineral

analogs.

14. Identify powder patterns not in the JCPDS file or find other compounds that might yield

a similar pattern. Cell dimensions, space group, name, chemical formula.

15. By using Crystal Data as described under II-l (above) I have avoided problems described

under II-3 and II-4 (above).

16. Whether the material on hand has been characterized crystal lographically and in particular to look for the original paper through references given.

17. Tend to use the Tables mainly to find out previously determined information.

18. 1. To identify certain materials with measured cell parameters.

2. To check similar type structures.

OTHER

Can't recall a specific example, but I often have an unknown crystal for which I have

chemical information (elemental analysis by electron microprobe) and limited optical

crystal lographic data, e.g., whether substance is anisotropic and if so, whether uniaxial or biaxial, plus some idea of refractive index. Using Crystal Data as a source

of information I may be able to pick out likely possibilities and be thus aided in

choosing the next step towards identifying the unknown.

1. Find possibly similar structures to one being determined.

2. Find if structural or symmetry information on a particular compound is available.

3. Search for information on modes of twinning, either listed in Crystal Data or in

literature references cited.

36
APPENDIX C

APPLICATIONS OF CRYSTAL DATA SPACE-GROUP TABLES AND NOWACKI'S SYSTEMATIC TABLES (1 1-8)

INDUSTRIAL

1. Compounds with certain space groups were predicted to have properties which we wanted

to study. The Space-Group Tables provided a starting point: determining what compounds

had those space groups so that substituted compounds might also be studied.

2. To establish that phases Sr7Sn(P0i+)G, Sr7Zn(P0i+)6, etc. were isostructural with

Bii,(Si0O3-

3. Searching for compounds with similar structures.

4. a) When unit cell parameters and space group are necessary for new compounds,

b) Identification of possible isomorphs.

5. To simplify identification of space group for technician.

6. For developed alloys, to determine if alloy is what was expected.

7. Identifying crystal variants of VO2.

8. For locating isostructural compounds.

9. To assist in space group determinations.

10. Occasionally.

UNIVERSITY or COLLEGE

1. Interested in possible correlation between chemical class and space group.

2. Group-subgroup relationships. Also for quick check of our early results.

3. Theoretical relations of symmetry to structure.

4. To determine space group of an organometallic molecule, prior to complete singlecrystal structural analysis.

5. Use in single-crystal ESR, NMR work.

6. Frequency analysis.

7. Crystal structure determination.

8. Whenever I determine the space group of an unknown crystal. I use Donnay tables in

Crystal Data.

9. Occasionally to check or verify or establish a space group.

10. Mainly to provide illustration examples and data for lectures.

11. See my reviews of the 1st and 2nd editions for comments on uses, and examples in re- prints. [See response 4 (University or College) in Appendix B.]

12. To find similar material for comparison.

13. Very occasionally I have needed names of other compounds in the same space group to help out a colleague in physics.

37
14. Mineral identification.

15. To find illustrations of different crystal structures for teaching.

16. Checking unknowns.

17. Statistical use.

18. Seldom.

19. Both are on the shelf adjacent to the Determinative Tables but rarely get used. The

Space Group Tables get a little use. Nowacki's table just doesn't seem conducive to use.

20. Rarely and only for look-up purposes.

21Only for interest.

GOVERNMENT and NATIONAL LABORATORIES

1. A very useful means of quickly finding related minerals (and inorganic compounds).

2. Search for isomorphous compounds of explosive or oxidizer nature so as to make mixed

crystals of same.

3. To look for likely isostructural materials and/or trial structures.

4. Space group determination of new minerals.

5. Nowacki is interesting but has not proven very useful.

OTHER

1. Theoretical study of crystal systematics.

2. Sometimes. c

r

38
NBS-114A (REV. 9-78)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS TN 1112

Jr.Gov*t Acfcesstwi No. 5. ftaci|i[i«tf*Ac<i«$5.i«&Wo<

4. TITLE AND SUBTITLE

USER EVALUATION OF CRYSTAL DATA PRODUCTS AND SERVICES;

QUESTIONNAIRE ANALYSIS AND IMPACT

5. Publication Date June 1980

6. Performing Organization Code

7. AUTHOR(S) J. K. Stalick, A. D. Mighell, and R. J. Boreni

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (-srree(. City, state. ZIP)

Same as item 9.

13. Type of Report & Period Covered

Final

W^^^m^iSJcyCo^"^^

15. SUPPLEMENTARY NOTES

I TGocuiBent describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTR^iQT (A 200-woTd or less tactual summary ol moat significant information. If document includes a significant bibliography or

literature survey, mention it here.) A survey was made of the needs of the users of Crystal Data Determinative Tables

and related products and services of the NBS Crystal Data Center. The results indicate

a high frequency of use of Crystal Data , with particular application to materials

analysis and design. The survey suggests a need for the development of a rapid and

inexpensive method of unit-cell determination as well as education of the scientific

community in the use of the single-crystal method for identification of unknown materials. More complete coverage and consolidation of entries are also suggested. The

necessity for computer-based methods of data base dissemination is indicated, with

particular importance for research applications.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unleas a proper name;

separated by aemicolons)

Computer dissemination; crystal data; identification; materials analysis; materials

design; NBS crystal data center; user evaluation;

18. AVAILABILITY [X^Unlimited

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BIBLIOGRAPHIC SUBSCRIPTION SERVICES

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subscription: $20.

Superconducting Devices and Materials. A literature survey issued

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