The perfect-pairing valence states of some later second-row elements

Abstract

The perfect-pairing or multiconfigurational valence states of P, S, and Cl appropriate to PF₅, SF₆, and ClF₃ have been studied. Optimum 3s, 3p, and 3d or 4s orbital exponents and values for the valence state promotion energy have been obtained. It is demonstrated that 3d orbitals in multiconfigurational valence states are more contracted than in the corresponding ‘spectroscopic’ configuration. In most cases further contraction by the coulombic field of the ligand atoms is required in order that the 3d orbitals contribute significantly to bonding. The valence state of the second-row atoms in charge-transfer structures is considered. Results for the multiconfigurational valence state are compared with those for the single-configurational valence state and the resonance valence state.