Localised molecular orbitals in self-consistent field wave functions. Part X. The nature of electronegativity

Abstract

The expression for the ionic bond energy which was developed in Part IX leads to an improved understanding of the nature of electronegativity. This coincides exactly with Mulliken's definition of this quantity, but the connection with Pauling's definition is less exact. It would be exact were the amount of charge-transfer within a bond proportional to the electronegativity difference between the two atomic orbitals which form the bond, but this is not generally true of the theoretical atomic charges which we have at present. If, in fact, this proportionality does emerge in the future, then all three definitions of electronegativity will coincide exactly. The question of the modification of the electronegativity of an atomic orbital is discussed, and it is clear that this is only appreciable inside a multiple bond.