4s orbitals in phosphorus

Abstract

The contraction of 4s orbitals in the 3sp³ 4s multiconfigurational valence state of P in PF₅ due to the coulombic field of the ligand atoms is investigated. 4s orbitals do not contract as much as 3d orbitals. The valence state promotion energy for the configuration involving 4s orbitals becomes greater than for the corresponding 3d orbital containing configuration. 4s orbitals should not participate in bonding so much as 3d orbitals. The sizes of 4s orbitals in a number of spectroscopic states are investigated. The results demonstrate that 4s orbitals are not as polarizable as 3d orbitals.