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NBSIR 81-2341 

Chemical Thermodynamic Data Banks 

National Bureau of Standards 
National Measurement Laboratory 
Chemical Thermodynamics Division 
Washington, DC 20234 

August 1 981 
Interim Report 


Preoared for 


ice of Standard Reference Data 
. r ional Bureau of Standards 
shington, DC 20234 


NBSIR 81-2341 


David Garvin, Vivian B. Parker and Donald D. Wagman 

National Bureau of Standards 
National Measurement Laboratory 
Chemical Thermodynamics Division 
Washington, DC 20234 

August 1 981 
Interim Report 

Prepared for 

Office of Standard Reference Data 
National Bureau of Standards 
Washington, DC 20234 

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary 


Table of Contents 


1 Introduction 1 

2. Evolution of Data Evaluation in 

in Chemical Thermodynamics 2 

3. Description of Data Banks 5 

3.1 Information Resources 5 

3.2 Evaluation of Data 7 

3.2.1 The Thermochemical Data System 7 

3.2.2 Treatment of Individual Papers 9 

3.2.3 Values for Chemical Thermodynamic 

Properties 10 

4. Thermodynamic Data Banks at the 

Institute for High Temperatures 11 

5 What of the Future? 14 

References 15 

Figures 18 

Chemical Thermodynamic Data Banks* * 

David Garvin, Vivian B. Parker and Donald D. Wagman 
National Bureau of Standards 
Washington, D.C. 20234 

A substantial critical evaluation of chemical thermodynamic measurements 
on inorganic and C-j^ organic compounds has recently been completed. This provides 
selected values for some 14300 substances, based on a collection of 250,000 measure- 
ments. This work is placed in a historical context of three earlier comprehensive 
evaluations of thermochemical data. 

During the course of this work data banks of several types have been developed: 
bibliography, extracted unevaluated data, evaluated measurements (catalogs of 
reactions) and selected chemical thermodynamic properties for individual substances. 
The design, structure and use of those data banks are described. 

The course of modern data evaluation, based on these files, is discussed 
briefly in terms of tests for inter-measurement consistency and automated 
solutions of large networks of data. 

A complementary thermodynamic data system developed at the Institute for High 
Temperatures, Moscow, USSR is described briefly. Proposed international activities 
are outlined. 

Key words: chemical thermodynamics; data evaluation; data banks; information 

systems; networks of data; standard reference data; thermochemistry. 


Presented at the American Chemical Society Meeting, Atlanta, GA., March 1981 

1 . 


The purpose of this paper is to describe several data banks that 
have been developed as aids in providing compilations of evaluated chemical 
thermodynamic data. They are also becoming available to the thermodynamics 
community as information resources. 

The first data resources to be described are those developed at the 
Chemical Thermodynamics Data Center at the National Bureau of Standards. They 
have been used primarily for the evaluation of thermochemical data. 

Also to be described is a second set of data banks developed primarily 
for use in the evaluation of thermophysical data. This set of data banks and 
an associated data management system have been developed at the Institute for 
High Temperatures of the USSR Academy of Science, Moscow. 

These data banks reflect only part of the world wide activity in the 
evaluation of chemical thermodynamic data. Some other major activities are 
mentioned very briefly in the final section of this paper. There are also 
data dissemination and calculation systems that are being developed to simplify 
retrieval and use of thermodynamic data. This rapidly growing activity is not 
reviewed here. 

To begin with it is advisable to define the terms being used here. 
"Thermochemical properties" are those that involve chemical reactions and 
mixing processes such as enthalpies of reaction combustion, solution and dilu- 
tion; Gibbs energies from equilibrium constants, electromotive cell measure- 
ments, and mixing experiments; entropy and heat capacity changes. In all of 
these chemical and physical (mixing) processes the chemical identity of the 
substance in the system changes. "Thermophysical properties" are those that 
pertain to single substances and mixtures that remain essentially unchanged 
during a process. They include PVT properties, entropy, heat capacity, and 
enthalpy changes accompanying changes of temperature and pressure, Gibbs en- 
ergy functions, enthalpies of vaporization and transition, and all other as- 
pects of phase changes. 


These two types of properties are illustrated in figure 1. The 
horizontal arrows for reactions apply to changes in thermochemical properties, 
the vertical arrows to changes in thermophysical properties with temperature. 

"Chemical thermodynamic properties" is the name given here to the 
aggregation of thermochemical and thermophysical properties. It includes all 
of those properties needed for a study of chemical equilibria and heat effects 
of reactions as a function of temperature, pressure and composition (of mix- 

The data banks developed at NBS are of several types: 

° Data extracts of thermodynamic measurements 
(substance/property index) 

° Bulletin of Chemical Thermodynamics 

(Inorganic chemistry section) 

0 Catalogs of evaluated Chemical Thermodynamic 

° Selected Values of Chemical Thermodynamic 

Properties (NBS Tech. Note 270) 

From our point of view the first three are aids to the preparation of the 
fourth: "Selected Values." This is a data bank that contains our recommen- 

dations on the thermodynamic properties at 25 °C for inorganic compounds and 
low molecular weight organics. It has just been completed and is the fourth 
full-scale evaluation of chemical thermodynamic data with which NBS has been 
associated in the past fifty five years. The data banks are best considered in 
the context of this activity. 

2. Evolution of Data Evaluation in Chemical Thermodynamics 

The nature and scope of thermochemical data evaluation activities have 
undergone a series of changes in the past 55 years, both in the collection and 
storage of thermochemical data and in the actual data evaluation process itself. 
A brief history of this evolution is in order. 


The International Critical Tables under the editorship of E. Washburn at NBS 
published a set of tables of heats of formation in 1929. These tables [1] were 
compiled by F. Russell Bichowsky, Naval Research Laboratory, and represented 
the first modern attempt to collate all the published data involving enthalpies 
of reaction and to prepare self consistent tables of selected values of en- 
thalpies of formation. 

Approximately 3700 inorganic and C-j - organic compounds were listed, with 
either an enthalpy of formation, of dilution, or of transition. Also included 
was the measurement type, by code, and the reference: a shorthand documentation. 

These 3700 total data items were obtained from a total of 1113 literature 
references. These references were abstracted, indexed and coded by compound and 
type of measurement. Bichowsky developed this as a hand written 3x5 card file. 
This was the data bank. (Conservatively it must have had close to 12000 3x5 
cards of pertinent information). The evaluation process itself was a completely 
manual, sequential approach of making selections, one compound and value at a 
time, building relationships and networks until a stable set of values for the 
enthalpies had been developed. 

This manual, sequential approach has dominated thermochemical data 
evaluation and is still being used. Only during the past decade has the computer 
based simultaneous solution approach become important. More on this later. 

This early data bank was maintained and added to and in 1936 Bichowsky and 
Rossini [2] published their "Thermochemistry of the Chemical Substances," which 
updated the enthalpies of formation, reevaluating and reassembling a self-consistent 
set of best values for approximately 6000 (inorganic and C-j - C 2 organic) sub- 
stances. Phase transition enthalpies were included. The total number of data 
items was 6600. The mesurements used were described tersely and compared in 
the text. There were now 3750 references. The 3x5 card data bank had in- 

3 _. 

creased to 22000 items. 

By 1940 it was quite obvious that the tables and maintenance of the data files 
could no longer be a part-time "extracurricular" activity for one individual. 

A formal program was undertaken at NBS headed by Frederick D. Rossini. 

Donald D. Wagman joined the staff in 1940 and William H. Evans in 1947. It was 
decided taht the scope of teh work must be enlarged, that evaluating only the 
ArH's could be both misleading and incomplete, that both the Gibbs energy and 
entropy should be included. When the volume "Selected Values of Chemical Thermo- 
dynamic Properties," NBS Circular 500 [3] was published in 1952, a line entry 
in Series I, on the formation properties, contained not only A^H°, but also 


AfG°, log K.p, S°, Cp, and A^Hq. The phase transition properties (Series II) 
covered were AH, T, AS, P, AC . The number of data items was 15000 based on 


8500 references. The card bank expanded to 50000. The tables were documented 
by reference citations only. 

This expansion of the tables meant that the user now had data for the 
prediction of equilibrium constants and also could correct them to temperatures 
other than the reference point, 298.15 K. 

The. expansion also had a major impact on the data evlauation process. Gibbs 
energy and entropy data could be used to confirm enthalpy measurements and the 
combined set could be used to predict values for which there was no direct reli- 
able measurement. This meant that data evaluation became more complex and re- 
quired more decision making. 

It is now 1981 and NBS has just completed the fourth major evaluation of 
chemical thermodynamic data. Originally conceived as a revision of Circular 500, 
it is a greatly expanded, completely reevaluated self-consistent set of data. 

It has been issued as NBS Technical Note 270 in eight parts over the past 16 
years [4]. A combined volume will be issued later this year. It covers the 
formation properties of 14,300 substances and has 26,000 data items, half of 
which are enthalpies of formation. We estimate that 60,000 references were 


used, and that these produced 180,000 cards in our compound/property index. 

A sample page from the final section of NBS Tech. Note 270 is shown in Figure 2. 
The documentation for this work has not been published. Our plans are des- 
cribed later in this paper. 

The growth and changing scope of compiled chemical thermodynamic data are 
displayed in Figures 3 and 4. 

It became increasingly clear by the later sixties that new methods must be 
developed to cope with the explosion of the literature and the more complex 
nature of the evaluation process. We turned to the computer for help in 

(1) staying on top of the literature (simplify the abstracting of data) 

(2) evaluating and intercomparing measurements (3) updating tables, and 

(4) documenting and disseminating the information. The developments reported 
in the next section reflect this change of procedure. 

3. Description of Data Banks 

The NBS data banks mentioned at the beginning of this paper were developed 
in the course of the evaluation of chemical therodynamic measurements for the 
NBS tables "Selected Values of Chemical Thermodynamic Properties." The data 
banks are of two types: 

° information resources 

° evaluated data 

3.1. Information Resources These are of three types: bibl iography , microform 

copies of papers and extracts of data. The last, the "card file" mentioned 
earlier, is the principal resource. It contains many types of information, all 
needed for the evaluation of data: 

° Experimentally measured enthalpies of reaction, fusion, 

vaporization, sublimation, transition, solution 
and dilution. 


° Vapor pressures, solubilities, chemical equilibria and 
EMF measurements. 

° Heat capacities, experimental and statistically calculated 
entropies . 

° Molecular structure and energy level data. 

0 PVT data and correlations of properties with structure. 

All of this information is organized by compound and then by the property 
measured. In order to keep this data bank current, staff members of the Chemical 
Thermodynamic Data Center scan the primary literature and Chemical Abstracts 
each month, select articles, and abstract them. A typical data extract (on one 
measurement on one compound) is shown in Figure 5. 

This index is now in two parts. Up to 1969 each information unit was 
written by hand on a 3 x 5" card. Since then the abstracts have been keyboarded 
into a computer file and the hard copies of them have been produced by a complex 
report-writing program. This has reduced sharply the routine labor required of 
the data abstractors and at the same time has created an archival file of raw 

The hand-written file covering chemical thermodynamics up to 1969 has been 
microfilmed and is being sold by the NBS Office of Standard Rererence Data. It 
contains images of 156,000 cards covering about 40,000 articles. 

The computer based file, covering chemical thermodynamics since 1969, is 
available on site at NBS-Gai thersburg (as a card file) and has been distributed, 
in part, but only for special cooperative projects. Distribution of the entire 
file to the public is being considered in connection with the development of an 
on-line retrieval system. In the meantime, the limited version that appears in 
the Bulletin of Chemical Thermodynamics should serve as an effective guide to 
the literature [5]. 

The Bulletin is an annual current awareness service. It contains indexes to 
published thermodynamic and related studes on: organic substances and mixtures. 


inorganic substances, biological and macromolecular systems, and reports on current 
research throughout the world. It is issued under the auspices of IUPAC, edited by 
Prof. R.D. Freeman, Oklahoma State University, and published by Thermochemistry , 
Inc., Stillwater, Oklahoma. A typical section of a page from the Bulletin is 
shown in Figure 6. 

3.2. Evaluation of Data The development of machine-readable evaluated chemical 
thermodynamic data is a result of the automation of parts of the final stage of 
the evaluation process in the Chemical Thermodynamics Data Center. "Machine 
readable" must be emphasized. Data banks similar to the ones to be described 
here existed in the pre-computer era. The evaluation process itself has two 
major parts: 

* evaluation of each set of measurements reported in an 
individual paper 

° combining the acceptable measurements from the 

various sources to obtain selected, reliable values 
of properties. 

The process has been discussed in detail elsewhere [6, 7, 8]. It is 
described briefly here starting with a brief discussion of the interconnected 
nature of thermodynamic data. 

3.2.1. The Thermochemical Data System 

All thermochemical measurements are relative, yielding changes in properties 
for processes. Thermochemical properties of a system also are functions only of 
the initial and final states and are independent of the path between the reactants 
and the products. These facts and what it is possible to measure control the 
structure of the thermochemical data system. There are two features that become 
apparent when a large number of such measurements are examined. First there is 


usually a very limited number of replicate measurements for any particular 
reaction. Intercomparison of many supposedly identical measurements is not a 
major part of the evaluation process. 

Second, there often are several chemically distinct experiments or sets 
of experiments that lead from a particular reactant to a particular product. 

We call each of these distinct sets a "measurement pathway." The phenomenon 
is illustrated in Figure 7 for a few compounds of beryllium. It shows six 
pathways leading from Be to BeO. They involve measurements on six other com- 
pounds, each of which may be part of other networks. Because changes of thermo- 
chemical properties are independent of the path, all six paths from Be to BeO 
must lead to the same result, in the absence of experimental error. 

The multiple measurement path phenomenon adds a dimension to the evaluation 
of chemical thermodynamic data that is absent from many other evaluation efforts 
extensive quantitative cross checks. This multiple path phenomenon is a major 
feature. The extensive crosslinking in the thermochemistry of lithium compounds 
is displayed in Figure 8. The many possible intercomparisons make it possible 
to select a highly consistent data set. 

The large data networks, such as Figure 8, are maps for linear algebra 
problems. Thermochemical measurements can be reduced, formally, to equations 
involving only the addition and subtraction of properties of compounds, and 
these appear only to the first power. An example is given in Figure 9 in which 
the measurement for a hydration process is decomposed into three terms, the 
enthalpies of formation of each substance from its chemical elements. Given an 
interconnected set of such equations, the enthalpies of formation can be solved 
for and then the "best values" for the processes reconstructed. For many years 
the solution of such networks has been done by hand, but now computer assisted 
solutions are becoming important. 


That such large thermochemical networks should be and are being solved using 
computer programs is due to the imagination and foresight of two groups of thermo- 
chemists. In the early 1960's Daniel Stull, Dow Chemical Co. proposed a system 
in which all thermochemical measurements would be put into computer files and the 
entire set for all inorganic chemistry could be solved at one time. This concept 
was developed by A. N. Syverud [9]. Shortly thereafter J. Brian Pedley, 

University of Sussex, proposed a computerized system designed for rapid updating 
of tables and for coordinating the work of several groups of data evaluators [10]. 

He has used it to produce the CATCH Tables [11] and the Sussex - N.P.L. tables 
on organic compounds [12]. These computerized approaches have been merged by us, 
expanded in a cooperative program between NBS and the University of Sussex, and 
used on large networks. 

3.2.2. Treatment of Individual Papers 

The first step in solving a data network, by computer or not, is the 
preparation of the input data. This is the most difficult step. The data evaluator 
must verify the work reported in each paper, develop an exact statement 
describing the chemistry for each process, and reduce the measured value to a 
consistent set of conditions (temperature, pressure, atomic masses etc.). The 
overall accuracy must be estimated. All of these acts require the evaluator 
to have a broad knowledge of chemical thermodynamics. This preparation of the 
input is the most time consuming part of the entire evaluation process. It is 
over 80% of the work. 

The results of each of these reanalyses can be summarized succinctly as 
shown in Figure 10: chemical reaction, property, value, uncertainty, reference 

and comments. They can be used directly as input to a machine solution of a 
thermochemical network problem. These reanalyses are also accumulated to form 
a catalog of evaluated thermochemical measurements that can be used to document 
the data evaluation. 


We expect to produce the documentation of the NBS Tables "Selected Values of 
Chemical Thermodynamic Properties" in the form of such catalogs, supplemented by 
commentary concerning special problems and tables of thermal functions used in the 
process. This is instant documentation in a detail that has not been practical 

One such catalog has been published. It covers the thermodynamics of compounds 
of thorium and is an experiment in highly structured, detailed documentation with 
the minimum of prose [13]. 

3.2.3. Values for Chemical Thermodynamic Properties 

The second part of the evaluation process is the simultaneous solution of the 
network of thermodynamic equations to get the formation properties of the compounds. 
This is, in effect, the reconciliation of data from many laboratories. The network 
is an overdetermined set and has been solved by a robust procedure involving 
both least sums and least squares treatments. [6] Several iterations may be 
necessary because this is the first point in the process at which estimates of 
interlaboratory agreement and accuracy of methods can be made reliably. 

The output from a network solution is a set of selected values for the 
AfH°, A^G° and S°’s of the compounds being studied. This solution has a property 
that is not well recognized. Because the measurements are all linked together, 
a change in one part of the network will cause changes in most of the A^H's , etc., 
while the best values for most of the individual processes will remain almost the 
same. This situation is the basis of pleas by evaluators that the user avoid 
mixing property values from several tables. It also explains why tables of 
thermochemical data are constructed to cover the full range of chemical compounds. 

Because the totality of inorganic thermochemistry is still too large for one 
solution to be practical, a series of solutions has been made, usually for com- 
pounds of one element at a time, group by group across the periodic table from 
right to left. (As the results of each solution are entered into the data bank 
they become available as fixed data for later solutions. This keeps all solutions 


consistent with each other.) Solutions for compounds of eight elements: Th, 

U, Li, Na, K, Rb, B, and Cs, have been made by machine. Earlier solutions 
were made by hand, using a sequential technique. 

The computer file of selected values is being used to produce the forthcoming 
NBS Tech. Note 270-8, the last in the series, and will be used to produce the com- 
bined volume for the entire series. With this computerized data bank it will be 
very easy to convert all values to SI units (from calories at 1 atmosphere to 
joules at 10 pascal.) This data bank will also become part of the thermodynamics 
module of the Chemical Information System sponsored by NIH and EPA. 

Let us return for a moment to the catalog of evaluated thermodynamic 
measurements. This catalog will outlive our "Selected Values" because new measure- 
ments will force modification of the selections. The catalog, supplemented with 
new data, and operated on by existing programs will permit an instant update. 

This would have been impractical using the older, manual, sequential methods. 

4. Thermodynamic Data Banks at the Institute for High Temperatures 

A very active thermodynamic data evaluation group at the Institute for 
High Temperatures of the USSR Academy of Sciences, Moscow (IVTAN), headed by 
L.V. Gurvich, publishes two sets of tables. They are "Thermodynamic Properties 
of Individual Substances" [14] and "Thermal Constants of Substances," [15] The 
former is analogous to the JANAF Thermochemical Tables [16] and the latter [15] 
is similar to NBS Technical Note 270, but also includes transition properties. 

In recent years the preparation of these volumes has been supported by a specialized 
data base management system that contains extensive data banks. Professor Gurvich 
has provided a description of this very attractive, flexible data system, which 
is given below in a slightly modified form. 

The data bank on thermodynamic properties was created in the chemical 
thermodynamic department of the Institute of High Temperatures of the USSR 
Academy of Sciences (IVTAN). Unlike most other data banks, the IVTAN data bank 
does not accumulate the data recommended in various reference books. It contains 


or generates the thermodynamic properties data for a wide temperature range 
on the basis of critical analysis of all primary literature sources. This data 
bank is used in the conversational mode using the "Image" subsystem on an 
Hewlett-Packard 3000 computer system. It contains a number of disc files, one 
file for each compound. Data for different isomers and also gaseous and con- 
densed phases of the same substance are stored in separate files. 

The system consists of a set of programs and data bases. The data bases now 
include the following: 

A) Auxiliary data such as fundamental constants, atomic masses etc. 

B) Input data used for the calculation of thermal functions: These 

data include molecular constants for gases and values of heat 
capacity enthalpy change and phase transition characteristics 
for condensed substances. All the data are selected by expert 

analysis of the primary literature. 

C) Experimental data on equilibrium constants of chemical reactions 

and vapor pressures of substances. 

D) Intermediate constants obtained by statistical treatment and 
critical analysis of data (B) and (C), e.g. reduction of high 
temperature data. 

E) Thermochemical constants (enthalpies of formation, enthalpies of 
sublimation, dissociation energies, ionization potentials, etc.) 
based on analysis of the primary literature and data from base (D). 

F) Tables of thermodynamic properties, e.g. thermal functions, and 
related data for each substances. 

The program set includes tens of programs and program modules providing for: 

A) Treatment of primary experimental and theoretical data accumulated 
in bases (B) and (C). 


B) Calculation of thermal functions of substances in gaseous and 
condensed phases over a wide temperature interval using different 
approaches in order to get the best possible accuracy for each 

C) Estimation of uncertainties of the thermal functions taking into 
account the reliabilities of the selected values of constants 
and method of calculation. 

D) Statistical treatment of primary experimental data contained in 
base (C) using the calculated thermal functions. 

E) Calculation of a consistent set of thermochemical constants for 
all compounds of a given element using data from base (E). 

F) Calculation of the final table of thermodynamic properties for a 
given compound including equations fitting the tabulated thermal 
functions and equilibrium constants for the reaction of atomization 
(or evaporation) . 

G) Management of all parts of the data bank. 

The data for more than 1000 substances have been accumulated in the IVTAN 
data bank up to the present. They cover all substances considered in the first 
three volumes of "Thermodynamic Properties of Individual Substances" and some 
substances from the last, fourth volume of this series. 

In the continuation of this work, IVTAN plan to enlarge the list of elements 
and compounds, to introduce a bibliography and short descriptions, and to create 
a data base on direct results of experimental measurements of the enthalpy and 
free energy of chemical reactions. A number of new programs will be written 
also for more accurate calculation of the thermal functions of simple polyatomic 
gases, for obtaining an interconsi stent set of thermochemical values for a given 
number of chemical substances from primary experimental data, etc. 


5. What of the Future? Where is chemical thermodynamic data evaluation going? 

The problem for the future is the rapid updating and effective delivery of 
thermodynamic data. Already, the major compilations of evaluated data are aging. 

Suppose that a new set of tables of evaluated data is to be issued in 1985. 

At least 25,000 new measurements will have to be considered and added to the 
catalogs. This is the bottleneck. The assessment of the individual paper has 
not been automated successfully although the process can be aided by calculational 
programs and graphical displays. Thus the answer must be to use all evaluative 
resources throughout the world in a cooperative program. 

CODATA, the Committee on Data for Science and Technology, is developing such 
a program. The first phase is the highly successful international Task Group on 
Key Values for Thermodynamics which provided new recommendations for one hundred 
fifty substances that are base points for many thermochemical measurements. [17]. 
The second phase is a plan for a much larger multinational thermodynamic data 
^yaluation consortium that might produce the next round of thermochemical and 
thermophysical tables. This is being developed by the CODATA Task Group on 
Internationalization and Systematization of Thermodynamic Tables. 

An example of what this might mean is shown in Figure 11. Here we have 
a series of independent groups (on the left) each contributing its output to 
an international system that would, in turn, serve the individual users. 

The cooperative scheme would reduce the overlap in services that exists at 
present, and provide the users with a single set of reconmendations and do this 
more rapidly. By splitting up the work, by exchange of data, and by common 
development of computer procedures the evaluation groups would greatly simplify 
their presents tasks. 

If all this can be done, the future will indeed be bright for the user of 
thermodynamic data. 



1. Bichowsky, F.R., "Thermochemistry: Heats of Formation under Constant 

Pressure (Heats of Solution, Heats of Transition)" in Washburn, E. W., 
editor, International Critical Tables of Numerical Data, Physics, 

Chemistry and Technology" McGraw Hill Book Co., N.Y. 1929, vol . V pg 169-213. 

2. Bichowsky, F.R. and Rossini, F.D., The Thermochemistry of the Chemical 
Substances , Reinhold Publ . Co., N.Y., 1936, 460 pp. 

3. Rossini, F.D., Wagman, D.D., Evans, W.H., Levine, S. and Jaffe, I., 

"Selected Values of Chemical Thermodynamic Properties", NBS Circular 500 
(1952), 1268 pp. 

4. Wagman, D.D., W.H. Evans, V.B. Parker, I. Halow, S.M. Bailey, and 
R.H. Schumm, "Selected Values of Chemical Thermodynamic Properties", 

U.S. Nat. Bur. Standards Tech. Note 270-3 (1968); idem, Tech. Note 270-4 
(1969); Wagman, D.D., W.H. Evans, V.B. Parker, I Halow, S.M. Bailey, 

R. H. Schumm, and K.L. Churney, Tech. Note 270-5 (1971); Parker, V.B., 

D.D. Wagman, and W.H. Evans, Tech. Note 270-6 (1971); Schumm, R.H., D.D. Wagman, 

S. M. Bailey, W.H. Evans, V.B. Parker, Tech. Note 270-7 (1973); Wagman, D.D., 

W.H. Evans, V.B. Parker, R.H. Schumm and R.L. Nuttall, Tech. Note 270- 8 
(1981), U.S. Govt. Printing Office, Washington, D.C. 

5. Freeman, R.D., editor, Bull. Chem. Thermodynamics (Thermochemistry , Inc. 
Stillwater, Oklahoma) vol. 22 (1979). 

6. Garvin, D. , V.B. Parker, D.D. Wagman and W.H. Evans, "A Combined Least 
Sums and Least Squares Approach to the Solution of Thermodynamic Data 
Networks" in B. Dreyfus, editor, Proc. Fifth Biennial Int. CODATA Conf . , 
Pergamon, N.Y. 1977, pg 567. 


7 . 

Wagman, D.C., D. Garvin, V.B. Parker, W.H. Evans, J.B. Pedley and 
P.M. Burkinshaw, "Handling and Evaluation of Large Networks of 
Thermochemical Data", Seventh Int. CODATA Conf . , Kyoto, Japan, Oct. 8-11, 1980. 

8. Wagman, D.D., D. Garvin, V.B. Parker, R.H. Schumm and J.B. Pedley. 

"New development in the evaluation of thermochemical data". In National 
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Spec. Publ . 572, U.S. Govt. Printing Office, Washington, D.C. 91980), 
pp 53-55. 

9. Syverud, A.N. and Klein, M. (Periodic Reports on USDC-NBS Contract 
CST 1165), Dow Chemical Co., Midland, Mich., 1964-65. 

10. Guest, M.F., Pedley, J.B. and Horn, M., "Analysis by computer of 
thermochemical data on boron compounds", J. Chem. Thermodynamics, (1969), 

1, 345. 

11. Pedley, J.B. (ed.). Computer Analysis of Thermochemical Data (CATCH Tables) , 
University of Sussex, Brighton. Data selectors and tables issued: 

Cox, J.G., "Halogen Compounds" (1972); Pilcher, G., "Nitrogen Compounds" 

(1972); Pedley, J.B. and Iseard, B.S., "Silicon Compounds" (1972); 

Head, A.J., "Phosphorus Compounds" (1972); Barnes, D.S., "Cr, Mo and W 
Compounds" (1974). 

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Data: Organic and Organometal 1 ic Compounds." University of Sussex, 

Brighton, England (1977). 

13. Wagman, D.D., R.H. Schumm, and V.B. Parker. A Computer-Assisted 
Evaluation of the Thermochemical Data of the Compounds of Thorium . 

NBSIR 77-1300. U.S. Nat. Bur. Standards, Washington, D.C. (1977). 


14. Glushko, V.P., L.V. Gurvich, G.A. Bergman, I.V. Veits, V.A. Medvedev, 

G.A. Khachkuruzov, and V.S. Yungman, eds. "Thermodinamicheskie 
Svoistva Individual 'nykh Veschestv", vol . 1, parts 1 and 2 (1978), 
vol . 2, parts 1 and 2 (1979), Izdatel'stvo "Nauka" Moscow. 

15. Glushko, V.P., V.A. Medvedev, G.A. Bergman, L.V. Gurvich, V.S. Yungman, 

A.F. Vorob'ev, V.P. Kolesov, L.A. Reznitskii, G.L. Gal'chenko, and for 
various volumes, V.V. Mikhilov, M. Kh. Karapet 'yants , V.P. Vasilev, 

V.N. Kostryukov, N.T. Ioffe, G.G. Malenkov, N.L. Smirnova, V.F. Baibuz, 

V.I. Alekseev, I.L. Khodakovskii , K.B. Yatsimirski i , and B.P. Biryukov, 
editors, "Termicheskii Konstanty Veshchestv", Vol. 1 (1965), Vol. 2 (1966), 
Vol. 3 (1968), Vol. 4, part 1 (1970), part 2 (1971), vol. 5 (1971), 

Vol. 6, part 1 (1972), part 2 (1973), Vol. 7 in 2 parts (1974), vol. 8 in 
2 parts (1978), Vol. 9 (1979); Viniti, Moscow. 

16. Stull, D.R. and H. Prophet, JANAF Thermochemical Tables, 2d Ed., 

Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. (U.S.), (1971) 37. 

Chase, M.W., J.L. Curnutt, A.T. Hu, H. Prophet, A.N. Syverud and 
L.C. Walker, - 1974 Supplement, J. Phys. Chem. Ref. Data (1974) .3, 

311-480. Chase, M.W., J.L. Curnutt, H. Prophet, R.A. McDonald, A.N. Syverud, 
- 1975 Supplement, J. Phys. Chem. Ref. Data (1975) 4., 1-175. 

Chase, M.W., Curnutt, J.L., R.A. McDonald, A.N. Syverud, J. Phys. Chem. 

Ref. Data (1978) 7, 793-940. 

17. CODATA Task Group on Key Values for Thermodynamics J.D. Cox. Chairman (1978). 
"CODATA Recommended Key Values for Thermodynamics 1977." CODATA Bulletin 28. 
CODATA, Paris, Idem (1980). "Tentative Set of Key Values for Thermodynamics. 
Part VIII". CODATA Special Report No. 8. CODATA, Paris. 














1. A thermodynamic cycle involving a chemical reaction at two temperatures 

2. Sample entries from the table on compounds of sodium from NBS Tech. 

Note 270-8. The highlighted items are new material, showing expansion 
from NBS Circular 500. All properties values (highlighted or not) 
are the result of new evaluations. 

3. Chemical thermodynamic properties included in the International 
Critical Tables, Bichowsky and Rossini, NBS Circular 500 and 
NBS Tech. Note 270. 

4. Growth of compiled chemical thermodynamic data over a fifty year period 

5. Extract of Data. The contents summarize one set of measurements of a 
property of a single compound. This is the useful information unit in 
chemical thermodynamics. 

6. Section of a page from the Bulletin of Chemical Thermodynamics showing 
the substance, property measured (two letter code) and reference. 

7. A Thermochemical network showing the measurement paths leading from 
elemental beryllium to beryllium oxide. 

8. Lithium Thermochemical Network. Each node (box) is a compound and 
each line is a measurement. The common starting point at the left 
is Li(^) and the top two compounds in the next column are Li ( g ) 
and Li (aq, std. state). Rectangles are enthalpies, diamonds are 
Gibbs energies and hexagons are entropies. 

9. Thermochemical process showing relationship of the measured enthalpy 
to enthalpies of formation. 

10. Reaction Catalog. Examples of the stylized summary of evaluated data. 
The form actually used is machine readable. 

1 1 . International Cooperation in Thermodynamic Data Evaluation. A 
possible organization of a consortium. 



T 2 

+ B 

+ B 


H 2' H 1 

(G 2 - HjJ/Tj 









CO co 

I ® 

1 r*» 
to ^ 
03 a; 

~ o 


2 ra 

0- .2 

£ o 


■o I 

2 w 


03 (0 
£ T3 
I- C 
_ (0 

o </5 


5 => 
o g 

■ ■ u. 

o = 


(0 O 
> ••= 
_ ra 
13 z 

03 " C - 















































a f H 

a f G 


4 f H 0 

H-H 0 

ICT B&R C500 TN 270 

X X X X 










4H tr 

4S tr 

P T 
r TR' 1 TR 











TN 270 











2840 CTR) 

Data Items 





4,200 CTR) 





















BaCl 2 taq ,B00H 2 O) 

Sobol, L.G., and Selivanonva, N . M . , t Zhur. F i z . K h i m . 
43, 2937-2938 (1969) 

Heas. heat of reaction of N a H S 0 4 and NaHSO^.HgO with 
BaClg(aq), plus heats of solution, at 25 C in isothermaL- 
jacket calorimeter. 

BaCl 2 (800H 2 0) + NaHS0 4 . HgO ( c ) = BaS0 4 (c) 

+ NaCl(800H 2 0) + HCl(800H 2 0] + HgOtliq) 

iAH = -6.7 + 0.10 kcal/mol 

BaC l 2 691442 


47. OSMIUM Os 


















Mn(c) + FeSlc) — MnS(c) + Fdc) 



Mn(liq) - H ; (g> 



Mn - Fe - O(liq) 













Al (c) 


See next page for Figure 8. 

NaBr(c) + 2H 2 0(C) = NaBr-2H 2 0 (c) 

AH = -19.24 + 0.05 kJ/mol 

= A f H (NaBr-2H 2 0) -A f H(NaBr) -2A f H (HO) 

Y + u = (-19.24 + 0.05) kJ/mol = X 3 - X ] - 2x 2 





Li Thermochemical Network 




OBSERVED VALUE +- UNCERT.: 37.0 +-4.5 

REACTION: TH'3N4(C) = 3 TH'N(C) + 0.5 N2(GS') 


ADJ'D BY 0.65 USING ESTD. CPITH3N4] = 39.33 + 
0.00624T - 533000/T2 . 


70, 3937 (1966) . 


Coordinated Projects 
Shared Expertise 
Shared Work Load 

Common, Consistent Wortd Wide 

Data Bank Use 



NBS-114A (REV. 2-80 



2. Performing Organ. Report No. 

3. Publication Date 



August 1981 

SHEET (See instructions) 

NBSIR 81-2341 


Chemical Thermodynamic Data Banks 


David Garvin, Vivian B. Parker, Donald D. Wagman 

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions ) 


7. Con tract/ Grant No. 

8. Type of Report & Period Covered 



1 | Document describes a computer program; SF-185, FIPS Software Summary, is attached. 

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant 
bibliography or literature survey, mention it here) 

A substantial critical evaluation of chemical thermodynamic measurements on 
inorganic and C-. -Cp organic compounds has recently been completed. This provides 
selected values for some 14300 substances, based on a collection of 250,000 measurements 
This work is placed in a historical context of three earlier comprehensive evaluations 
of thermochemi cal data. 

During the course of this work data banks of several types have been developed: 
bibliography, extracted unevaluated data, evaluated measurements (catalogs of reaction:.) 
and selected chemical thermodynamic properties for individual substances. The design 
structure and use of those data banks are described. 

The course of modern data evaluation, based on these files, is discussed briefly 
in terms of tests for inter-measurement consistency and autmoated solutions of large 
networks of data. 

A complementary thermodynamic data system developed at the Institute for High 
Temperatures , Moscow, USSR is described briefly. Proposed international activities 
are outlined. 

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons) 

chemical thermodynamics; data evaluation; data banks; inforamtion systems; networks of 
data; standard reference data; thermochemistry. 

[X 1 Unlimited 

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