A comprehensive tabulation of the standard enthalpy change, ΔH°, entropy change, ΔS°, and free energy change, ΔG°, for the formation of ion clusters from ion‐molecule association reactions is given. The experimental methods which are used to derive the data are briefly discussed. For some experiments, dissociation energies of ion clusters are reported and listed under the category of ΔH°. The relationship between ΔH° and dissociation energy is discussed in the text.