Studies of hypervalent iron.

The iron(IV), (V) and (VI) oxidation states are of great interest because of their role in catalytic oxidation/hydroxylation reactions. This report summarizes the information currently available on the kinetic and chemical properties of the water-soluble ions of FeO4(2-), FeO4(3-), and FeO4(4-), their protonated forms and/or simple complex derivatives. The discussion includes their radiation-induced formation, decay kinetics, reactivity with other compounds, determination of their respective pKa values as well as spectral properties.