Chemical hardness of metal ions in the gas phase: a thermochemical approach

Abstract

The heterolytic dissociative version of Pauling's bond-energy equation, proposed earlier for an AB molecule, has now been generalised for molecules of type AB_n in order to rank a number of multivalent cations in terms of their gas-phase chemical hardnesses. The chemical hardness of a cation is found to be related to its charge and size, and Klopman's frontier-orbital energy. The results are used to systematise the gas-phase affinity displayed between a monovalent anionic ligand (specifically, a halide) and a metal ion.