PC Database Available for Predicting Thermochemical Performance of Materials

Chemical manufacturers, material suppliers, and researchers in science and industry now have an easy-to-use computer program for help in predicting the performance of chemicals in their custody, including storage, shipping, and use in the laboratory and in manufacturing. The personal computer database, Chemical Thermodynamic and Energy Release Program, known as CHETAH, is available from the National Institute of Standards and Technology.

CHETAH, Version 7.0, is an important tool for estimating both thermochemical properties and predicting certain "reactivity" hazards associated with a pure chemical, mixture of chemicals or a chemical reaction. The program is designed to conveniently and accurately calculate properties such as heat capacity, enthalpy, entropy and Gibbs energy of reactions as a function of temperature at 298.15 kelvin.

Malcolm W. Chase, chief of the SRDP at NIST, says this is accomplished through a knowledge of only the molecular structure of the components involved by an implementation of the well-known Benson's second order group additivity method for gases, and through ionic group additivity for inorganic solids. The thermochemical estimation part of the program is currently not capable of handling organic solids or liquids, Chase adds.

There is an "energy release evaluation" option that provides the user with information about the ability of a material to decompose with violence if subjected to severe impact. Among other functions in CHETAH are the ability to build compounds from library or user-entered groups, gases or solid crystals; build crystals from ionic groups; enter private thermochemical data; and classify mixtures for flammability and estimate lower flammable limits for a substance.

The CHETAH computer program was developed originally by a group of researchers and scientists in the American Society for Testing and Materials' Committee E-27 on Hazardous Potential of Chemicals. ASTM asked NIST to review and evaluate the product and make it available to the public through the institute's widely known Standard Reference Data Program.

Since 1968, the NIST program has been responsible, under an act of Congress, for coordinating the evaluation of numerical data that describe the chemical and physical properties of well-defined substances.

NIST Special Database 16: CHETAH, Chemical Thermodynamic and Energy Release Program, Version 7.0, is available for $350. It is designed for any MS DOS or PC DOS computer using DOS 2.1 or greater and at least 512 KB memory.

To order CHETAH, Version 7.0, contact the Standard Reference Data Program, A320 Physics Building, NIST, Gaithersburg, Md. 20899-0001, (301) 975-2208, fax: (301) 926-0416, e-mail: SRDATA [at] enh.nist.gov (SRDATA[at]enh[dot]nist[dot]gov) (via Internet).

As a non-regulatory agency of the Commerce Department's Technology Administration, NIST promotes U.S. economic growth by working with industry to develop and apply technology, measurements and standards.