The electronic structure of chalcogen hexahalogenides

The electronic structure of the chalcogen hexahalogenides AX₆, where A = S, Se, Te and X = F, Cl, and the anions ACl₆^2? is calculated using the discrete variational Xα method (DVM Xα) within a basis of numerical Hartree—Fock (HF) functions. A dependence of some chemical properties of these compounds on the calculated distributions of their electronic densities is considered. The characteristics of chemical bonds in hypothetical hexachlorides ACl₆ are compared with those of AF₆ and the anions PCl₆^? and SbCl₆^? isoelectronic with SCl₆ and TeCl₆. An explanation of the electron affinity (EA) changes along the series AX₆ is suggested. Some peculiarities of the electronic structures of ACl₆^2? determining their stability and stereochemistry are discussed. The calculated energies of electronic transitions in SeCl₆^2? and TeCl₆^2? are compared with available absorption spectroscopy data.