Determination of atomic hybridization in molecular orbital theory: a valency method

A simple method which makes use of the relation between valency and the occupation number of natural hybrid orbitals is proposed to determine atomic hybridization in molecular orbital theory. The method is free from any external criteria and it is applicable to all atoms in molecules of any symmetry. Illustrative results at the ab initio STO-3G, 4-31G and 6-31G levels are given for LiH, HF, NH3, H2O CH4, CF4 and C2H4. The dependence of hybridization on the basis set is discussed