A change in the oxidation state of iron: scandium is not innocent.

Through extensive molecular modelling of Fe(III/IV)-oxo and Fe(III)-hydroxo complexes it is shown here unambiguously that the assignment of the iron oxidation state of a Sc(3+)-capped iron-oxygen species should be revised. Iron in this Lewis-acid capped metal-bound oxygen system is Fe(III), coinciding with water as a secondary axial ligand to scandium.