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Issues in Science and Technology Librarianship
Winter 2018

Electronic Resources Reviews

ThermoLit: NIST Literature Report Builder for Thermophysical and Thermochemical Property Measurements

A. Ben Wagner
Chemistry and Physics Librarian
Science and Engineering Information Center, University Libraries
University at Buffalo
Buffalo, New York


In simplest terms, the ThermoLit database is a literature reference search overlay to the latest incarnation of the massive Thermodynamics Research Center (TRC) data sets (Wilhoit and Marsh 1989) that were compiled over several decades and have been augmented under the auspices of the National Institute of Standards and Technology (NIST) since 2000 (Frenkel et al. 2005). Designated as NIST Standard Reference Database #171, ThermoLit is freely available via the Internet.

Data Origins and Related Databases

TRC has had a long history under different sponsors (Kroenlein 2005). It started in 1942 under the auspices of the National Bureau of Standards (the predecessor agency of NIST), moving to Carnegie Institute of Technology, then Texas A&M University, and finally back to NIST in Boulder, Colorado in 2000.

Originally, TRC thermodynamic data was published as collections in voluminous sets of three-ring binders. For example, the long-running American Petroleum Institute Research Project 44 measured physical and thermodynamic properties of hydrocarbons and related compounds as well as their NMR, mass, UV, and IR spectra. Although these binders are still found on the shelves of some research libraries, more likely these sets have been discarded or moved to remote storage, now relics in our digital age. However, the data quality and scope are still virtually unmatched.

ThermoLit's search query page gives only one clue as to the origins of the literature references and associated thermodynamic properties. In the fine print of the copyright statement at the bottom of the page, the acronym TRC appears without any explanation. It is difficult to piece together a complete picture of the content and computer architecture for the ThermoLit database from the publicly available documentation and journal articles. However, it is clear that underlying ThermoLit is the NIST ThermoData Engine (TDE) software package, the primary product of the Thermodynamics Research Center. TDE provides access to critically evaluated thermodynamic and transport property data based on the principles of dynamic data evaluation. It uses published experimental data, predicted values and optional user-supplied data. TDE provides access to single-phase thermodynamic and transport property data, VLE, LLE, and SLE data for over 40,000 binary mixtures and 11,000 ternary mixtures, and does automated evaluation of most of those properties. Two versions of the ThermoData Engine exist, the first being a subset of the second:

  1. Pure Compounds - NIST Standard Reference Database #103a
  2. Pure Compounds, Binary Mixtures, Ternary Mixtures, and Chemical Reactions - NIST Standard Reference Database #103b

A related subscription-based database, the Web ThermoTables (WTT), is not evaluated in this review. Like ThermoLit, WTT is underpinned by the ThermoData Engine software and is available in two editions:

  1. NIST/TRC Web Thermo Tables (WTT) Professional Edition (NIST Standard Reference Database #203): This is a searchable database of 32 critically evaluated thermodynamic properties for over 23,300 pure compounds and over 512,500 evaluated data points, with a focus on organics. Included is all numerical property data from both the TRC Hydrocarbons and Non-Hydrocarbon Thermodynamic Tables sets. It supersedes the old TRC TABLE/Thermodynamic Tables (Wilhoit and Marsh 1989).
  2. NIST/TRC Web Thermo Tables (WTT) Lite Edition (NIST Standard Reference Database #202): In contrast to the Professional Edition described above, this Lite Edition contains information on approximately 150 commonly-used compounds and access to a total of 86,407 evaluated experimental data points.


ThermoLit's subtitle, NIST Literature Report Builder for Thermophysical and Thermochemical Property Measurements, hints at the fact that this free version returns only a list of literature references that contain the data of interest, not the actual property data. To get the actual data values, one either pays for the above noted subscription databases or retrieves and hunts through the full text of the literature references cited in the ThermoLit generated report.

ThermoLit covers at least 24,700 compounds linked to 4 million experimental property data points and 14,400 reaction data points. Binary mixtures, the largest segment, are linked to over 2.4 million data points. The focus is on organic and non-metallic inorganic compounds. All counts are as of September 7, 2011. (Kazakov et al. 2012, p. 23.)

Underlying ThermoLit, the ThermoData Engine, and Web Thermo Tables is the massive TRC SOURCE database containing over 4.8 million experimental data points. (Frenkel et al. 2001; Kazakov et al. 2012; Wilhoit and Marsh 1999) which:

Incidentally, the NIST underlying data processing systems are also used to provide data quality control for articles published in five journals:

Search Interface

Searches require input of a combination of specific compound(s) and properties. There are no options for direct bibliographic searching such as title keywords or authors. According to Dr. Kroenlein, this lack of bibliographic search features is intentional, as there are much better tools for keyword-based searching, whereas ThermoLit fills a gap for compound-based searching. The one and only search query screen (Figure 1) is reached by clicking on the prominent 'Build a NIST Literature Report' button in the center of the home page or on the small 'Property' link on the top command line.

Figure 1: ThermoLit's search query screen

The system guides you through the entire search query building process via drop down menus. To perform a search:

  1. Select the desired System Type (pure compounds, binary mixtures, or tertiary mixtures).
  2. Enter compound names, molecular formulas, or CAS Registry Numbers. Registry numbers are included for all substances and are the recommended search option. Truncation of chemical names is possible by using the asterisk (*). Note that you must hit the Search Button and retrieve a specific substance, either before the next step or after you specify the property of interest before any results appear.
  3. Select one of the 11 Property Groups, e.g., critical properties, phase transition properties, or refractive index. Note that all transport properties (viscosity, thermal conductivity, electrical conductivity, and diffusion coefficients) are within the single Transport Properties group.
  4. Depending on the property group selected, specify a specific property, e.g., critical temperature, and the phase (solid, liquid, gas, etc.) as prompted.

Note that only a maximum of 20 compounds are displayed for a name or molecular formula search, making registry number searching preferable. Molecular formulas must be entered using proper case; i.e., 'C6H5ClO' for 4-chlorophenol.

One other search limitation is that only one property and one phase can be searched at a time. It is not possible to see all transport properties of phenol in a single pass, for example. However, the search system is generally fast, and one does not need to reenter the compound each time. Simply change the property drop down selections (Property Group, Property, Phase). Results update automatically as you change the property drop down menu items.

Video demonstrations are available at

Report Results

Relevant literature references with the conditions for the measured property are displayed. To save the results, click on the button 'Add result to Report Draft'. By then proceeding to the Report Draft page, one can save the list of references as a PDF file. Remember that only the subscription versions gives one the actual property value, so users of ThermoLit will need to retrieve the full-text of the reference to get the actual data point(s). Clicking the -Add result to Report Draft' button each time after subsequent search queries will append the results to the Report Draft.

The draft report can be viewed and saved as a PDF file by clicking on the -Generate Report PDF button'.

Other Functionality

The web design of the entire site is simple to the point of being Spartan, with plain black text, white background, and no images. This plain interface tends to belie the extensive, rich data that is just a few mouse clicks away. In addition to the Property (search) and Report Draft (results) pages, the following pages are linked from the home page:


Unfortunately, NIST has done very little to promote ThermoLit, nor has it received any publicity in scientific library and information circles. In fact, a search of major Ebsco databases, SciFinder, INSPEC, Compendex, Scopus, and Web of Science turns up zero hits on the term 'thermolit'. Hence, this review appears to be the very first publication discussing this free, valuable database that has been available for a number of years. In fact, to determine the scope the database and ThermoLit's relationship to other NIST thermodynamic databases and software systems, this reviewer had to contact the principal NIST investigator, Dr. Kenneth Kroenlein, who is listed on the Help page. One can only hope that NIST will make a priority of promoting ThermoLit and the related subscription databases.

Although ThermoLit does not directly provide data values, it is far quicker and more complete than consulting print compilations of thermodynamic data or smaller electronic databases. One can quickly establish if a property has been measured and exactly in which literature reference(s) the desired property is found.


I would like to thank Dr. Kenneth Kroenlein, Group Leader of the Thermodynamics Research Center, Applied Chemicals & Materials Div. of the Material Measurement Laboratory of the National Institute of Standards and Technology for reviewing my manuscript for factual errors and providing additional links to web pages about their products.


Frenkel, Michael, Chirico, Robert D., Diky, Vladimir, Yan, Xinjian, Dong, Qian, and Muzny, Chris. 2005. ThermoData Engine (TDE): Software implementation of the dynamic data evaluation concept. Journal of Chemical Information and Modeling 45(4), 816-838. DOI: 10.1021/ci050067b

Kazakov, A., Muzny, C.D., Kroenlein, K., Diky, V., Chirico, R.D., Magee, J.W., Abdulagatov, I.M., Frenkel, M. 2012. NIST/TRC SOURCE Data Archival System: The next-generation data model for storage of thermophysical properties. International Journal of Thermophysics 33(1):22-33. DOI: 10.1007/s10765-011-1107-7

Kroenlein, K. 2005. TRC History [Internet]. Thermodynamics Research Center, Applied Chemicals and Materials Division, National Insititute of Standards and Technology. Available from:

Wilhoit, R.C., Marsh, K.N. 1989. Automation of numerical data compilations. Journal of Chemical Information and Computer Sciences 29(1):17-22.

Wilhoit, R.C., Marsh, K.N. 1999. Future directions for data compilations. International Journal of Thermophysics 20(1): 247-255. DOI: 10.1023/A:1021407003786

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