BOND-CLEAVAGE ENERGIES FOR MOLECULES AND THEIR ASSOCIATED RADICAL IONS

Ordinary two-electron covalent bonds may be broken homolytically, to form free radicals, or heterolytically to form a cation and an anion. This article describes a simple approach employing reaction calorimetry and electrochemistry that can be applied to many ions that are stable in solution. Heats of heterolysis (DELTAH(het)) are obtained immediately from the reverse process, the heat of reaction of the cation and the anion to form the covalent bond. DELTAH(het) values can be converted into heats of homolysis by determination of the oxidation potential of the anion and the reduction potential of the cation and extended to cleavage of radical ions.