A new approach to the relationship between bond energy and electronegativity

The familiar equation whereby Pauling related heteronuclear bond energies DA–B to the electronegativity difference Δχ (=∣χA − χB∣) and the homonuclear bond energies DA–A and DB–B has been the subject of critical scrutiny for at least half a century. A modification to this equation that combines the concepts of electronegativity and hardness/softness can be rewritten in terms of two quantities x and y, both having absolute significance. Both homo- and heteronuclear bond energies can be rationalised from these new equations. The quantities x are linearly related to Pauling electronegativities, while y appears to be a measure of an atom’s intrinsic bonding potential, related to size and availability of valence orbitals.

A modified version of Pauling’s bond energy equation can be derived from intuitive expressions for homopolar and heteropolar bond energies DA–A and DA–B in terms of the quantities x and y, which are related to electronegativity and hardness/softness.Figure optionsDownload as PowerPoint slide