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ThermoData Engine


TDE example 1
The purpose of ThermoData Engine (TDE)  is to provide critically evaluated thermodynamic and transport property data using the SOURCE database--a dynamically curated database established at NIST.  The critical evaluation is based on:
  • published experimental data
  • predicted values based on molecular structure
  • user supplied data (optional)

ThermoData Engine is the first product fully implementing all major principles of the concept of dynamic data evaluation formulated at NIST/TRC. This concept follows the model of an expert system, requiring a large electronic database capable of storing essentially all 'raw' experimental data known to date with detailed descriptions of relevant metadata and uncertainties. 

An inference engine combines these data with state-of-the-art property prediction schemes and heuristics that emulate the critical evaluation process of a domain expert.  Combined in one package, TDE generates recommended data compilations automatically 'to order'.  The NIST/TRC SOURCE data archival system, currently containing approximately 6.1 million experimental data points, is used in conjunction with ThermoData Engine as a comprehensive storage facility for experimental thermophysical and thermochemical property data. Currently, this database contains property data for approximately 24,000 pure compounds, 53,000 binary mixtures, 15,000 ternary mixtures, and 7,200 chemical reactions.  



  • Well-structured information from current and historical investigations on thermophysical properties of organic compounds
    • Full provenance on all experimental and estimated data that underpin critical recommendations
    • Proprietary data can be entered for inclusion in the evaluation, and the user can influence the evaluation process by changing relative data weights or by rejecting particular data sets
  • The ThermoData Engine fills the gaps in experimental data by the deployment of property prediction, enforces of consistency between related properties (including those obtained from predictions), provides for flexibility in selection of default data models depending on the particular data scenario, incorporates a large variety of models for secondary fitting, and allows saving of critically evaluated data in the ThermoML format.
  • TDE supports :
    TDE example 2
    • several equations of state for pure compounds (original and modified volume-translated Peng-Robinson, Sanchez-Lacombe, PC-SAFT, and Span-Wagner) and allows user to fit their parameters to experimental and predicted data
    • access to single-phase thermodynamic and transport property data, VLE, LLE, and SLE data, and does automated evaluation of most of those properties
    • special fitting equations for certain properties such as densities, critical, and transport properties are described by special fitting equations
    • phase equilibria data are described by activity coefficient models selected by the user from the set of supported models: Margules, NRTL, Redlich-Kister, UNIQUAC, van Laar, and Wilson. UNIFAC predictions are generated for mixtures covered by the various versions of the UNIFAC method, including NIST-modified UNIFAC model as well as with COSMO-SAC predictive model
    • phase diagrams, isotherms, and isobars based on those models can be calculated and drawn for the user's convenience
    • evaluation of the thermodynamic properties of chemical reactions such as enthalpies, entropies, Gibbs free energies, and equilibrium constants based on available experimental data as well as group contribution methods
  • TDE is capable to evaluate thermophysical properties and their uncertainties for multi-component material streams
  • The stored experimental data include calorimetric values for more than 7,200 reactions and reaction equilibrium data for more than 1,600 reactions
  • Enthalpies of formation are evaluated on the basis of stored experimental enthalpies of combustion and modified Benson group-contribution method
  • Up-to-date information on major publications on properties of organic compounds


  • pure organic compounds
  • binary mixture systems containing organic compounds
  • ternary mixture systems containing organic compounds
  • thermodynamic properties
  • thermochemical properties
  • transport properties

documentation and users guides

NIST ThermoData Engine 103a

Pure Compounds

Standard Reference Database Information

User Guide

NIST ThermoData Engine 103b

Pure Compounds, Binary Mixtures, Ternary Mixtures,  and Reactions

Standard Reference Database Information

User Guide

System requirements

PC with Microsoft® Windows® XP, Windows Vista, Windows 7, Windows Server 2003, Windows Server 2008,  Windows Server 2012, or Windows 10. At least 2 GBytes of memory is recommended.

Licensing Info

TDE is distributed by Standard Reference Data Program

National Institute of Standards and Technology, Gaithersburg, MD 20899.

Information for 103a Pure components database

Information for 103b, Pure, binary, ternary components and reactions database

NIST ThermoData Engine Database Citation Examples

We would appreciate acknowledgement if the software is used; please cite.


Data provided via the NIST ThermoData Engine+(SRD#103a or #103b)+[version] was used.

In a list of References:


Liability Statement

The data and other information in these computer files have been carefully extracted from the original articles by the authors and were checked for completeness by NIST/TRC personnel before posting. Neither the Journal publisher, nor its editors, nor NIST/TRC warrant or represent, expressly or implied, the correctness or accuracy of the content of information contained in these files, nor its fitness for any use or for any purpose, nor can they, or will they, accept any liability or responsibility whatever for the consequences of its use or misuse by anyone. In any individual case of application, the respective user must check the correctness by consulting other relevant sources of information.


The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high-quality copy of the program and database and to verify that the methods and data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the program and database





Created February 8, 2017, Updated June 2, 2021