ThermoML-2017 Revision of an XML based IUPAC Standard for Thermodynamic Property Data (IUPAC 2017-016-3-100)

Summary

It is intended to update the XML-based dictionary for storage and exchange of thermophysical and thermochemical data based on fundamental principles of phenomenological thermodynamics covering a wide variety of systems such as pure chemical compounds, multicomponent mixtures, and chemical reactions.

Upon completion of the project, the developed dictionary and corresponding XML schema could become an internationally accepted standard for thermodynamic data storage and exchange.

The coverage of the XML standard must be expanded to provide a standard for the multitude of engineering applications and research projects that utilize data as a key element of design.

Description

This project is to be considered as a revision of the 2002-055-3-024 “XML-based IUPAC standard for experimental and critically evaluated thermodynamic property data storage and capture”, which was successfully completed in 2006. From that project, a new XML-based IUPAC standard (ThermoML) was established for thermodynamic data communications (Pure and Applied Chemistry, 2006, 78, 541-612; https://dx.doi.org/10.1351/pac200678030541).

Initially, ThermoML provided support for communications of experimental, critically evaluated, and predicted data for thermodynamic properties of pure and multi-component mixtures of molecular compounds with comprehensive representation of uncertainties (JCED, 2003, 48, 2-13; 2003, 48, 1344-1359; and 2004, 49, 160-174). Prior to release as a standard, enhancements for aqueous electrolyte solutions and ionic liquids were included. In 2011, a revision was completed (IUPAC project 2007-039-1-024) which broadened the scope of ThermoML to support storage and exchange of thermodynamic property data for, (1) speciation and complex equilibria in aqueous and non-aqueous solvents, and (2) thermodynamic properties of biomaterials. Furthermore, the extension addressed experimental data in the primary literature, as well as derived equilibrium constants for reactions and the associated Gibbs energy, enthalpy and heat capacity data, including equation representation.

Thermodynamic property data for metallurgical systems play an essential role in Integrated Computational Materials Engineering and Design, which should be performed at the earliest stage of R&D. Yet, at present, there is no comprehensive data management system specifically designed for metallurgical data. This project will support communications for the prior properties and standards while expanding the XML for a few new properties, processing history metadata, and the phase characterization and assignment for thermophysical properties.

Major Accomplishments

Dec 2019 update - The task group met in Graz in 2017 during the ECTP conference. In this meeting the group members discussed the preliminary draft and already implemented changes to the XML structure of the new ThermoML standard.
Some of the major improvements are the restructured linking of attributes by key references, an improved representation capability for phases and reference states, better characterization of multi component substances, improved annotation of fields, new properties and all with maintaining backwards compatibility with the previous ThermoML version.
A summary of example files and other resources is available on the created github-page: https://github.com/usnistgov/thermoML

The task group members provided feedback and suggestions for improvements and more examples for use cases were created to test the updated schema.

Feb 2024 update - In November 2023, another project with NIST on a similar topic was approved (https://iupac.org/project/2023-008-1-024) and which should be informative to updating the existing standard. Practically, the Chair and several members are also members in that newest project and this project is being discontinued.