Temperature dependence of complex formation constants in aqueous solutions of metal acetates

The equilibrium constants of formation of inner- and outer-sphere cation-anion complexes (ion pairs) in aqueous solutions of different metal acetates in a wide temperature range have been calculated by integrating the density function of distribution of ligands around the cation. The standard Gibbs energies, enthalpies, and entropies of formation of 1: 1 complexes have been calculated. It has been shown that, in all solutions under consideration, contact and solvent-separated ion pairs coexist. A conclusion has been drawn that the temperature dependence of ion association constants is mainly determined by the temperature dependence of the water dielectric constant.