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[Critical IUPAC publication of solubility data] [CODATA]

NBS Tables


The National Bureau of Standards (NBS, now NIST, National Institute of Standards and Technology) published a large set of recommended values, “the NBS Tables of chemical thermodynamic properties” for inorganic substances and for organic substances usually containing only one or two carbon atoms (Wagman et al. 1982).

The NBS Tables are the result of one of the widest-reaching and longest-running critical assessment tasks ever. Wagman et al. (1982) make the following statements about the work:

“Separate reports are being prepared about the selection of the values in this book. They will list the measurements considered and those used, show how well the selected values reproduce the measurements, indicate corrections that were made, identify auxiliary data that were used, and give the bibliographic citation for each measurement. These reports are expected not only to document this book but also to provide a set of evaluated process data that can be used in future evaluations without repetition of all of the analysis we have to make. One such report has been prepared as an experiment, on the compounds of thorium (Wagman et al. 1977).”

Unfortunately, none of these envisioned reports ever appeared. Consequently, values in the NBS tables cannot be traced back to experimental data, nor can any statement be made about the quality or even adequacy of an individual value.


Values for the Gibbs free energy of formation, ΔfGm°, the standard molar enthalpy of formation, ΔfHm°, and the standard molar entropy, Sm°, are given for gaseous, liquid, and crystalline substances, for solutions in water, and for mixed aqueous and organic solutions. Values are not given for alloys or other solid solutions, fused salts or for substances of undefined composition. Compounds of the transuranium elements are not included.

Wagman et al. (1982) list 26’000 values for the chemical thermodynamic properties of 14’300 substances, counting separately the same compound in different phases and at different concentrations. Enthalpies of formation at 298.15 K dominate with 12’800 entries, with 4’400 values for Gibbs energies and 3’600 for entropies. Wagman et al. (1982) estimate that 60’000 references were used in the development of the tables, and that these produced 180’000 cards in their index to thermodynamic measurements.


The values of the NBS tables are still in widespread use in thermodynamic databases. The original publication by Wagman et al. (1982), a supplement to the Journal of Physical and Chemical Reference Data, is available online.