NBSIR 74-537

CODATA Guidelines on Reporting

Data for Chemical Kinetics

The CODATA Task Group on Data

for Chemical Kinetics

August 1974

Final Report

Prepared for The CODATA Symposium on Chemical Kinetics Data

for the Lower and Upper Atmosphere,

September 1974

Warrenton, Virginia

NBSIR 74-537

CODATA GUIDELINES ON REPORTING

DATA FOR CHEMICAL KINETICS

The CODATA Task Group on Data

for Chemical Kinetics

August 1974

Final Report

Prepared for The CODATA Symposium on Chemical Kinetics Data

for the Lower and Upper Atmosphere,

September 1974

Warrenton, Virginia

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent. Secretary

NATIONAL BUREAU OF STANDARDS. Richard W. Roberts. Director

CODATA Guidelines on Reporting

Data for Chemical Kinetics

Abstract

This document is a copy of the report, June 1974, of the

Task Group on Data for Chemical Kinetics of the Committee on Data

for Science and Technology (CODATA) . In this report recommendations are made about the reporting of experimental chemical

kinetics data.

The Report and its recommendations have been approved by

CODATA. They will be published in definitive form as CODATA

Bulletin No. 13.

Keywords: chemical kinetics, guidelines, recommended procedures

for reporting data, standardization, units

1
I. Report of the CODATA Task Group

on Data for Chemical Kinetics

on

The Presentation of Chemical Kinetics

Data in the Primary Literature

A set of recommendations entitled, "Reporting Experimental Data

for Chemical Kinetics," is here submitted to CODATA for consideration,

approval and publication.

The purpose of these recommendations is to ensure that accurate

rate measurements are preserved and not lost through inadequate

reporting. To this end the recommendations tell what types of data

and auxiliary information should be reported and also point out the

significant items of documentation that should be included. The

Task Group believes that adherence by authors to these relatively

few elementary recommendations when reporting experimental work can increase the durability of the results and improve the possibility of

evaluating and comparing related studies.

These are recommendations for the discipline of chemical kinetics

as a whole. They are part of a larger CODATA effort to provide guidelines for various branches of science. A more general document,

"Guide for the Presentation in the Primary Literature of Numerical

Data Derived from Experiments," has been prepared by the CODATA Task

Group on Publication of Data in the Primary Literature and published

as CODATA Bulletin No. 9, December 1973. It too should be studied by

kineticists interested in improving the quality of the published

literature. We have made use of ideas in it and, at times, have

included some of its statements verbatim in our recommendations.

General guidelines applicable to an entire discipline, however,

are not sufficient; detailed recommendations are needed for various

specialized types of rate measurements. The Task Group has made an interim attempt to do this for some sub-disciplines. These recommendations are given in Appendix I of the report . They should be

replaced by more comprehensive recommendations prepared by panels of

experts in each specialty.

The Task Group undertook this work at the request of CODATA.

Our starting point was a good set of guidelines prepared by

Academician V. N. Kondratiev. An expanded version was prepared and

circulated to about 1400 kineticists . More than 200 replies were

received, most of them containing substantive suggestions. The Task

Group has reviewed these comments and has incorporated many of them

in its present report. We are very grateful to our colleagues

throughout the world for their careful and constructive review of our work.

2
It is our hope that, through continued cooperation, kineticists

will be able to raise the accepted standard of reporting to a point

where guidelines on the subject become unnecessary.

s. W. Benson, Chairman K. U. Ingold

D. L. Baulch J. A. Kerr

E. T. Denis ov T. W. Newton

J. E. Dubois G. A. Schuit

J. Durup R. Tamamushi

D. Garvin V. I . Vedeneev

H. Hartmann H. G . Wagner

M. Koizumi

II. Reporting Experimental Data for Chemical Kinetics

Because of the widespread and growing use of the numerical results

of chemical kinetics research in other fields of science and technology,

it is important that those results can be properly compared, evaluated

and compiled for use by nonspecialists . Because of the variety of

techniques employed in chemical kinetics and the wide range of systems

studied, the quality of this reevaluation depends critically on the

standards of reporting in the primary literature. In these recommendations we give criteria for the presentation of experimentally determined numerical rate data.

Our criteria apply most specifically to kinetics papers in which

numerical data are reported. Our aim is to ensure that accurate rate

measurements are preserved and not lost through inadequate reporting.

In general we confine ourselves to measurements of macroscopic rate

constants ; these guidelines are not concerned with the interpretation

of rates in terms of mechanisms.

The recommendations are not necessarily applicable to all papers

in chemical kinetics. There are valuable studies of a general or semiquantitative nature to which many of our suggestions may be

irrelevant. We do not discourage the publication of these papers. We

do want sufficient information included in them so that the work can

be assessed. Nor are these recommendations a guide to literary style

or the organization of a paper. Our entire concern is with the factual

content

1 . General

We base our recommendations on the following principles:

(i) The work should be described in sufficient detail to allow

the equipment, conditions, procedure and, logically, the results to

be reproduced, and to allow the quality of the work to be appraised.

3
(ii) The results should be presented in a form that will permit

them to be reanalyzed and reinterpreted by others.

(iii) There should be an assessment of the accuracy and reproducibility of the numerical results.

In expanding these points in the following paragraphs we cannot

anticipate the consequences for all the many possible chemical systems.

We confine ourselves to points of general importance.

2. Experimental

2 . 1 Materials

The names of reactants, catalysts, ionic-strength adjusting

chemicals, third body molecules (gas phase reactions), etc. should be

given explicitly. Common names are often ambiguous and should be

clarified; abbreviations should be specified, particularly for ligands

in coordination compounds. The use of systematic nomenclature,

chemical formulae and chemical structure diagrams is encouraged. Whereever possible, precise composition and structure and, where appropriate,

stereo-descriptions should be given.

The origins, methods of purification and storage of reagents,

solvents and other relevant materials should be stated. Criteria

for purity, analytical results and known impurities should be

given.

Where solid phases are used, other information may be necessary,

such as the chemical composition, the structure (pellet, powder, film),

the microstructure (where possible), and a description of the solid's

pretreatment and history.

2.2 Apparatus

The report should include, either directly or by reference,

descriptions of:

(i) Materials of construction, particularly those in contact

with the reactants or products.

(ii) The reaction vessel including, where appropriate, dimensions,

surface-to-volume ratio, materials of construction and pretreatment.

Where the reaction does not occur homogeneously throughout the vessel

(e.g., in some high temperature processes or photolyses), the "effective

reaction volume", spatial distribution of the reaction or both should be

given.

4
(iii) All relevant ancillary equipment and measuring devices.

Performance capabilities should be stated for detection devices (noise,

baseline stabilities), thermostatting equipment (stability, temperature

profile), temperature measuring instruments, etc.

In the case of novel or complex apparatus it may be necessary to

supplement the description with a realistic diagram of important

features of the apparatus, giving dimensions and relevant geometry.

Construction details should be made available on demand.

Modifications to standard or previously used apparatus should

always be described.

2 .3 Experimental Methods

The account of the experimental method should include, either

directly or by reference:

(i) Description of the preparation of the reaction mixture,

any methods used for initiating the reaction and those used to

follow the course of the reaction.

(ii) An indication of the sequence of operations, in mixing or generating reactants, in analyzing the change and in separating products.

(iii) An explanation of the way in which any method is used,

with quantitative details, e.g., reactant concentrations generated,

detection conditions (signal-to-noise ratio), or wavelength and

extinction coefficient used in spectrophotometric measurements . For

photochemistry and radiation chemistry the spectrum (energy

distribution of the incident radiation), beam geometry and rate of

energy input are of particular importance.

(iv) The applicability of novel procedures should be justified.

(v) It must be made clear what physical properties are measured

and how they are related to the concentrations of the chemical species

or to their rate of change.

3 . Presentation of Results

In this section we consider general points common to most kinetics

studies. Problems peculiar to various sub-disciplines are considered

in Appendix I .

'

By "results" we do not mean meter readings but those typical

outputs of kinetics studies: the measured rate of reaction, the

stoichiometric change in the system, the dependence of rate upon concentration, the rate constants and their variation with temperature,

bond strengths, and so on.

5
3.1 General

(i) Whenever a rate is reported care should be taken to state

clearly to what process it refers. When possible the process should

be stated as a chemical equation.

Ambiguities in the meaning of the rate may occur for reactions

such as (1)

v.A + v„B + -» V U + V V + (1) A B u V

if stoichiometric numbers, v , other than unity occur. A clear

definition of the rate of reaction, R^^, is required. We recommend

use of the convention

R^= - I d[A] = - 1 d[B] = 1 d[U] = ... V, dt v„ dt V dt

A B u

= some function of concentrations (2)

(ii) The results should be reported in a form that does not

depend on interpretations made in the paper, still showing the

experimental scatter and with as little dependence as possible on theoretical assumptions. Some processing of instrument readings

is usually necessary before a convenient reporting stage is reached.

This is acceptable, but the relationship between the reported results

and the initial data should not be lost.

(iii) The procedures and expressions used to derive quantities

from direct experimental measurements, or from already processed

results, should be explained. At times the procedure may be relatively

trivial, but at least it should be outlined; in other instances a very

complete explanation or a worked example may be necessary.

(iv) The use of graphs to show trends, to compare data and as a basis for conclusion and generalization is valid and often extremely

valuable. Our experience suggests, however, that a graph is not

appropriate for recording accurately determined rate data. Inaccuracies

occur in transferring results to a graph and, unless the graph is

unusually large, the results cannot be recovered with sufficient accuracy for evaluation and reprocessing. For these reasons it is vital

that accurate numerical data be presented in tabular form.

When there is a large amount of data an acceptable alternative

may be an easily used analytical expression together with a graph

showing the deviation of the individual points from the expression

(e.g., see Blades, Int. J. Chem. Kin. 3_, 187 (1971)). However, in

experiments where several conditions change over the range of experiments (e.g., initial concentration or degree of conversion), tabulation

is strongly preferred.

6
As far as possible all tables and graphs should be selfexplanatory .

(v) Care should be taken always to include a comprehensive

statement, preferably in the tables, of the variables (pressure,

temperatures, concentrations, etc.) relevant to a particular rate or rate constant measurement. All relevant variables should be given.

For example, in flow experiments, the flow velocity and distance

should be quoted in preference to (or as well as) the reaction time.

The number of determinations on which a measured rate constant is

based should be included.

(vi) The amount of a product and /or reactant being analyzed or

the magnitude of the physical change being monitored should be given.

Sufficient data should be quoted to allow the degree of conversion to

be calculated. Possible perturbation of the reaction by the analytical

procedures should be discussed.

(vii) Negative results and unsuccessful experiments are often

important. Wherever relevant they should be reported.

3 .2 Rate Constants and Results Derived from Them

(i) All reported rate constants should be defined by giving an explicit mathematical statement of the pertinent rate equation, i.e., an expression equivalent to equation (2) above.

(ii) The formulation of the actual rate-determining step in a complex reaction is often difficult and subject to conflicting

interpretation. Such formulations are not discouraged, but for the

purposes of consistent data compilation, it is desirable that the

rate laws and rate constants based on principal species be given in

addition to other more speculative possibilities and that at some

stage a rate constant defined in terms of the net, or observed, reaction

be reported.

(iii) Rate constants are often derived by using numerical

analysis to fit the observed change in a system to a hypothetical

reaction scheme involving a number of variables, usually rate constants, some of which are known, some unknown. In such procedures:

(a) The reaction scheme should be justified, preferably on the

basis of independent experiments or theory.

(b) An indication should be given of the sensitivity of the fit

to the values assumed for the variables.

(c) The sensitivity of the fit to other possible models should

be indicated.

7
These conditions should be met whether analytical or numerical

analysis is being used, but they are particularly important for

computer modeling.

Where steady-state expressions are used to analyse results, the

validity of the steady-state approximation should be justified and

any uncertainty in the procedure estimated.

(iv) Where auxiliary data are used in deriving rate constants

and the like, the literature source should be given. If the

auxiliary data are measured or calculated, the methods used should

be described. In either case the accuracy of the data over the range

of conditions in which they are applied should be quoted.

In the case of thermodynamic data it is important to define the

standard state used.

(v) A variety of functions are used to express the rate constant,

k, as a function of temperature, T. We recommend the use of one of

the following foms:

k = A exp (-B/T) (3)

k = A't"^ exp (-B'/T) (4)

k = A-'t'^ (5)

where the A's, B's and n's are constants. Commonly, n in equation

(4) is preset on the basis of theory.

Unless there are overriding reasons, equations of these types

should be used to determine only two independent constants. When

energies, enthalpies and entropies of activation are derived, it must

be made clear which of these equations has been used.

3 .3 Errors: Accuracy and Precision

(i) At some stage in the reporting of experimentally determined

numerical data there should be a statement of the precision and accuracy.

The statistical or random uncertainty (precision) should be

estimated using an appropriate standard statistical technique. However,

it is only one component of the total error analysis and is not a sufficient statement of the reliability of the experiments.

Estimation of the other potential sources of error or limitations

of the work is more difficult. There are no clear rules; subjective

judgement is involved. However, these estimates of accuracy are more

important than estimates of precision because the difference between

values reported by two laboratories is often larger than the random errors.

8
(ii) Wherever possible the various sources of error, such as measurement precision, numerical analysis limitations, assumptions

made in processing the data or uncertainties in auxiliary data, should

be identified. The methods for estimating these errors should be

indicated

(iii) Precision . The quoted precision should be clearly defined,

e.g., is the standard deviation of the value being given or a multiple

thereof? It is important to specify the number of data being processed;

techniques appropriate to the sample size should be applied.

When least-squares methods are used in processing the data, it is

important to specify what quantity is minimized and/or what weighting

scheme is used. For example, is the sum of squares of absolute, or relative, errors minimized?

It is important to take account of the fact that in experiments

carried out over a range of a particular variable, say temperature,

results obtained at the extremes of the range are usually much less

accurate than those near the center. In these cases a weighted

least-squares procedure should be used.

(iv) When data are presented on graphs, realistic error bars

should be shown.

3.4 Units

It is extremely important that all physical quantities reported

should have their units clearly specified. Table headings and axes

of graphs should be labelled in dimensionless form, e.g., k/m^mol'-'-s"-'-,

and the units of quantities used in analytical expressions, e.g.,

Arrhenius equation, should be stated.

Units used in reporting the final results should be compatible

with the International System of Units (S.I.).

The unit of time should be the second. For concentration, the

S.I. unit is mol m~ , but permissible alternatives are mol dm" , mol

cm' and molecule cm" , which are all commonly used. Rate constants

may be given in any appropriate combination of these units.

The S.I. unit of energy is the joule.

The use of non-S.I. units, and especially the use of nonmetric

units, for reporting rate data is discouraged.

9
Occasionally there may be overriding reasons for using such units.

In these cases the author should give factors for conversion to S.I.

units. This may be done in a footnote: "Throughout this paper 1 torr = (101.325/760) kPa, and 1 kcal = 4.184 kj."

3 . 5 References

Pertinent references must be given for all methods, results and

auxiliary quantities quoted. In every case the reference cited should

be the actual reference consulted by the author .

Readily accessible references are preferred; authors quoting less

accessible references should indicate how they may be obtained.

References to long articles and books should cite specific pages

wherever possible.

4 . Accessibility of Data

Our recommendations request authors to be more explicit and more

careful in their reporting. We do not believe that their implementation

will require a substantial increase in the length of papers, except

possibly for 3.1 (iv), which recommends the use of tabulation of results

In most cases we expect that it will be sufficient to tabulate rate

constants and the associated experimental conditions (section 3.1 (v)).

Only in exceptional cases will more be required.

The ideal situation is to have all the relevant information in

the published article. However, if this is not practical, the supplementary material should be put in an auxiliary publication (submitted

together with a shorter manuscript) and either placed in a suitable

depository serx^ice or published as microform together with the article.

In any event, the details must be available to the public from some source other than the author. The means of obtaining such auxiliary

information must be clearly stated in the publication.

5 . Referee's Check List

One of the problems encountered by referees is that of keeping in

mind all the criteria outlined here. To assist in this we recommend

that referees be supplied with a check list on which our criteria are suitably itemized. A suggested form is given in Appendix II. It is,

of course, the prerogative of the referee to decide whether the items on the list are appropriate or relevant to the paper under consideration

10
Appendix I

Interim Recommendations Applicable to Specific Fields of Chemical Kinetics

In this appendix we supplement the general recommendations with

discussions of problems frequently encountered in interpreting reports

of research in the areas of homogeneous gas phase, liquid phase, solid

phase and heterogeneous reaction kinetics.

These are interim recommendations. They are not comprehensive.

We believe that all these areas require further scrutiny by experts

before more specific guidelines are prepared.

1 . Homogeneous Gas Phase Reactions

(i) It is usual in defining a rate constant to assume constant

volume conditions. In systems where the volume is not constant,

appropriate corrections should be made. This is particularly important

for shock tube and flow systems if the reaction is appreciably

exothermic or endothermic.

(ii) Pressure is often an important variable in gas phase

systems, particularly when addition and dissociation reactions are involved. Thus dissociation reactions, first order at high pressures,

become second order at low pressures, and analogous changes from

second to third order occur for addition reactions. Formulations of

the type (1) and (2) are often used to denote the reaction (in this

example, addition) in these two kinetic regions.

A + B -» AB (1)

A + B + M -» AB + M (2)

Although this practice is permissible, it is essential that reports

on such reactions include the pressure at which the measurements were

made and, if known, the order of the reaction under those conditions.

Also, the composition of the system, often just denoted by M, should

be given explicitly.

In studies at very high pressures where the gas behavior is far

from "ideal," it is preferable to express results in terms of concentrations rather than pressures.

(iii) Any effects due to reaction vessel surface should be

reported directly or by reference. If no tests were made, this should

be stated.

11
(iv) Modern kinetics techniques often involve reactants and

products in states far removed from thermal equilibrium. Beam studies

(neutral and ionic), flash photolysis, shock tube experiments and any

strongly exothermic or endothermic reaction may produce nonequi librium

conditions. In such cases every effort must be made to specify com- pletely the energy states or energy distribution of the species

involved. This may require extensive tabulation of measured crosssections, conditions of measurement (e.g., strength of electric fields,

pressure) and internal and kinetic energy of reactants and products.

2 . Liquid Phase Reactions

(i) The properties of the reaction medium often play a more

important role in reactions in liquids than in the gas phase. It is

important that the composition of the medium be specified in detail.

This may include a statement of the solvent used, its origin and

history (section 2.1), the composition of solvent mixture used

(vague statements such as "60% acetone-water" are not acceptable

without clarification), ionic strength, reactant concentrations and

concentrations of other species present that may affect the reaction,

e.g., hydrogen ion. Also, wherever possible, impurity concentrations,

including the presence of dissolved air, should be given and their

possible role considered.

(ii) It should be clearly stated whether the reported rate

constants are based on concentrations or activities.

(iii) When rate constants are defined in terms of minor, but

probably kinetically active species, the values used for the necessary

ionization or complexing constants should be quoted. If required,

information on the temperature coefficients of these constants should

also be included. As for all such auxiliary data, literature source

or measurement techniques should be given.

(iv) In liquid phase studies results are often reported in

terms of the transition state theory parameters AH^ and AS^. When

this is done:

(a) It is extremely important to state clearly the process and

the standard state to which these "thermodynamic" quantites refer.

Ambiguity may arise when overall rate parameters are interpreted in

tems of an assumed mechanism. It should be made quite clear whether

the Zffl^ and AS^ refer to the overall process, to an assumed rate

determining step, or to some combination of rate constants and possibly

equilibrium constants for reactions involved in the mechanism.

(b) It is helpful for compilation and evaluation and for users

of the data to have the Arrhenius parameters given as well as the

transition state quantities.

12
3 . Solid Phase Reactions

(i) Because rate processes in the bulk of a solid may be very

sensitive to the solid's structure and to the impurities present,

these should be specified (section 2.1). The "reactivity" of the

solid may be affected by such physical properties as specific surface

area, pore size and pore size distribution, and crystallite size and

distribution. Defects, impurities and potentially active centers

are similarly important. All these properties should be characterized

wherever possible.

(ii) It is necessary to specify the stage of the reaction to

which any rate parameters pertain since changes in the solid structure

may affect the reaction rate.

(iii) In the early stages of reaction, appearance and growth of

reaction centers will occur. It is desirable to give rate parameters

for these processes and the distribution of these centers through the

solid as well as parameters for the net reaction.

(iv) Kinetics of solid state reactions are affected by heat

evolution and absorption and hence by physical properties such as thermal conductivity. In such cases the effects of self -heating or cooling should be considered in deriving kinetic data.

(v) The extent of a solid state reaction is often expressed in

terms of the fractional reaction: the meaning of this term should be

clearly explained.

(vi) Any equation used to relate the variation of reaction rate

to extent of reaction should be stated and the terms defined. The

range of conditions over which it is applicable should also be stated.

(vii) The simple Arrhenius relation is often not applicable to

reactions occurring in solids. Where Arrhenius parameters are quoted,

the method used for calculating them should be explained.

4 . Reactions at the Surfaces of Solids

(i) The general criteria for the description of the solid

(section 2.1) should include the method of preparation. The pretreatment of the solid should be described.

(ii) Some attempt should be made to characterize the surface.

The surface area should be determined and, if possible, the concentration of active sites on the surface. With supported metal catalysts,

the metallic surface area and thence the dispersion of the metal should

also be determined. The methods used in these determinations should be

specified.

13
(iii) Information as to the texture of a catalyst or adsorbent

should be given, in particular, the particle size, the pore volume

and the pore size distribution. Methods used in determining the last

two quantities should be specified.

(iv) The kinetic equations used to calculate the rate constants

should be specified. Rates of reaction and rate constants may be

given per unit mass, per mole, or per unit area of the catalyst or adsorbent, but the units chosen should be clearly indicated. Where

possible, it may be convenient to express the rates of catalytic

reactions as turnover numbers, the number of molecules reacting per

site per second. The method used for determining the number of sites

should be described.

(v) Since concentration gradients in the pores of a catalyst

or adsorbent often influence rates, the data needed to evaluate the

degree of severity of this effect should always be given. Diffusion

limitations should be considered.

(vi) As for solid state reactions, the effects of self -heating

or self-cooling should be considered.

(vii) In systems involving gas flow over a surface, both total

flow and flow velocity may be important and should be specified.

14
Appendix II

Referee's Check List

This check list attempt to cover only the most important,

standard features to be considered in refereeing papers on chemical

kinetics. In many instances further unlisted points will require

comment

Referees are requested to indicate whether they consider the

particular point listed to be treated satisfactorily or whether

a suggestion for improvement is appended.

1. Apparatus and Procedures

Is the author's description of the

following items satisfactory?

(i) Reaction vessel

(ii) Ancillary equipment and

measuring device

(iii) Procedure

(iv) Calibration of apparatus

2. Materials

Has the author provided sufficient

information on:

(i) Origins and/or preparation, and

purity of reagents used?

(ii) Chemical formula, structure,

history, storage and pretreatment

of reagents and/or materials used?

Satisfactory Comment

Appended

15
Results

(i) Are sufficient primary data

presented to allow reworking of

the results independent of any

assumption or interpretations

of the author?

(ii) Are all the relevant variables

recorded for each set of rate

measurements presented?

(ili) Are the reported rates specified

unambiguously in terms of the

stoichiometric change in the

reaction?

(iv) Are all reported rate constants

' unambiguously defined in terms

of rate equations?

(v) Are the procedures and expressions

used to derive numerical results from

the data adequately explained and

their use justified?

(vi) Are error limits quoted and

justified for measured, derived,

and auxiliary quantities?

General

Is the referencing adequate?

Is the nomenclature clear?

Are all symbols defined?

Satisfactory Comment

Appended

16
NBS-114A CREV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. puhlic:ation or report no. NBSIR 74-537

2, Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLL

"CODATA Guidelines on Reporting Data for Chemical Kinetics"

5. Publication Date August 1974

6. Performing Organization Code

7. AUTHOR(S)

The CODATA Task Group on Data for Chemical Kinetics

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 316.0150

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

National Bureau of Standards

Department of Commerce

Washington, DC 20234

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less [actual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

This document is a copy of the report, June 1974, of the Task Group on Data

for Chemical Kinetics of the Committee on Data for Science and Technology (CODATA).

In this report recommendations are made about the reporting of experimental chemical

kinetics data.

The report and its recommendations have been approved by CODATA. They will be

published in definitive form as CODATA Bulletin No. 13

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

)

Chemical kinetics; guidelines; recommended procedures for reporting data;

standardization; units

18. availability [X Unlimited

For Official Distribution. Do Not Release to NTIS

1

' Order From Sup. of Doc, U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. CU

[X] Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCL ASSIFIED

21. NO. OF PAGES

16

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

22. Price

USCOMM-DC 29042-P74



)