Transition Metal Electronegativities (Configuration Energies) as a Function of Oxidation State (pp. 27-41)
Authors: Terry L. Meek and Leland C. Allen
Abstract: The transition metals differ from the main group elements in that those electrons that are not directly involved in bonding to other atoms are localized on the metal atom and should not be included in the calculation of electronegativity. Consequently there are different electronegativity values associated with different oxidation states of each metal. (In main group atoms, all valence electrons participate in bonding and there is no oxidation state dependence of electronegativity.) Transition metal electronegativities (configuration energies) are evaluated by calculating, for each metal in all oxidation states up to the highest known value, the mean multiplet averaged one-electron energy of all electrons that take part in bonding. For any given metal the configuration energy (CE) increases as oxidation state increases.
In any group, the increase of CE with oxidation state is most pronounced for the first row element and least for the third row element. In most groups, CE for a given oxidation state decreases from the first row to the second, then increases again to the third row (Groups 3, 4, 5 and 11 differ somewhat from this pattern). There is a general increase of CE for all oxidation states across the rows, but the detailed pattern of change is quite different for