Localised molecular orbitals in self-consistent field wave functions. Part IX. The ionic bond energy and dipole–dipole interaction energies

Abstract

The influence of bond polarity on the atomisation and bond energies of a molecule is studied. It is shown that the chemical bond is stabilised by its internal polarity, and the physical factors responsible for this are set out. The quantitative estimates show that the ionic bond energy is small (5–10 kcal./mole), and the covalent term is still responsible for most of the bond energy. The dipole–dipole interaction energies between polar bonds are very small (order of 1 kcal./mol) and they have the expected or classical sign. Certain overcomplicated equations given earlier have been simplified by regrouping the terms.