Theoretical Basis for d-Orbitals

Abstract

Since d-orbitals are central to the problem of valence shell expansion, we should first discuss the nature of d-orbitals. In the free atom, there are five d-orbitals, each of equal energy and having the electron distributions shown in Fig. 1. Although the degenerate energy level will be split by the field of the ligands, the angular parts of the orbital wave functions will remain unchanged. On the basis of angularity (geometry alone), d-orbitals should have considerable overlap with suitably oriented 2s or 2p orbitals on the ligand.