Zn in the +III Oxidation State

The possibility that the group 12 elements Zn, Cd, and Hg can exist in an oxidation state of +III or higher has fascinated chemists for decades. It took nearly 20 years before experiments could confirm the theoretical prediction that Hg indeed can exist in the +IV oxidation state. While this unusual property of Hg is attributed to relativistic effects, Zn, which is much less massive than Hg, has not been expected to have an oxidation state higher than +II. Using density functional theory, we have shown that an oxidation state of +III for Zn can be realized by choosing specific ligands with large electron affinities. We demonstrate this by a systematic study of the interaction of Zn with the ligands F, BO2, and AuF6, whose electron affinities are progressively higher (3.4, 4.5, and 3.4 eV, respectively). The discovery of higher oxidation states of elements can help in the formulation of new reactions and hence in the development of new chemistry.