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Where to find equilibrium constants? - A Guide

Numerous large compilations of equilibrium constant values have been published over the years, each having their own limitations, coverage and availability. This site is intended to offer a continuously updated overview with respect to a range of included metals and ligands, and the present-day availability of publications or computer databases. It is based on the article “Where to find constants” by W. Hummel, M. Filella and D. Rowland (Science of the Total Environment, 692, 49–59, 2019).

Existing compilations:

Non-critical IUPAC compilation

Critical IUPAC publication of equilibrium data

Critical IUPAC publication of solubility data

NBS Tables


NIST Critically Selected Stability Constants of Metal Complexes


NEA Thermochemical Database (TDB)