Bond Character in XYM-Type Molecules: Chlorine—Oxygen Compounds

Abstract

An internally consistent LCAO—MO method is presented for determining the bond characters in XYM-type molecules involving second-row elements. This treatment is based on Moffitt's ``atoms-in-molecules'' method, but utilizes valence-state electronegativities of the atoms involved rather than the generally unavailable valence-state ionization potentials and electron affinities. Results from the two methods compare favorably for C–O and S–O compounds. Application of the method to the oxygen compounds of chlorine shows that the chlorine atom 3d orbitals may significantly participate in the π bonding. A successful correlation between the calculated total π-bond orders and the Cl–O bond stretching force constants is obtained when a reasonable set of β(dπ) values is used, and the observed properties of the compounds are compatible with the calculated bond characters.