CHEMICAL HARDNESS OF METAL-IONS IN THE GAS-PHASE - A THERMOCHEMICAL APPROACH

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