A relationship between the molecular polarizability, molecular dipole moment and atomic electronegativities in AB and AB n molecules

Abstract

Electronegativity equalization considerations applied to diatomics and AB n molecules of C nv , symmetry lead to a simple relationship between the static molecular dipole moment m 0, the static polarizability α along the principal axis and the electronegativity difference Δ X between atoms A and B. The relationship is α = m 0 R/Δ X where R is the bond length (or height in the case of AB n ). Ab initio calculations are used to assess this equation. For single bonds it is found that Δ X is remarkably constant over a range of bond lengths, or moderately changing at most. However, Δ X is found to be sensitive to valence coordinates that can modify the hybridization of the atoms. For equilibrium structures the electronegativity differences determined in this work are found to be within the range spanned by other scales.