ferrateVII

FerrateVII, or ferrate(VII), refers to a proposed oxidation state of iron at +7 in ferrate oxoanions. In common ferrate chemistry, iron in the +6 state forms the ferrate(VI) anion [FeO4]2−, which is well known for its strong oxidizing power in alkaline aqueous solutions. Ferrate(VII) would hypothetically correspond to the anion [FeO4]−, with iron one oxidation state higher than ferrate(VI). However, ferrate(VII) is not known to exist as a stable, isolable species under ordinary laboratory conditions. The Fe(VII) oxidation state in oxoanions is not observed in stable salts, and attempts to generate FeO4− generally yield transient species that rapidly reduce or decompose.

Theoretical and experimental discussions of ferrate(VII) emphasize its extreme oxidizing potential and expected instability. In aqueous media, hydrolysis and redox chemistry would quickly limit any Fe(VII) species, leading to reduction to Fe(VI) or further disproportionation. In nonaqueous or highly specialized environments, some transient Fe(VII)-type species may be proposed, but none have been reliably isolated or characterized.

Because ferrate(VII) lacks stable, practical forms, it has no established applications and remains primarily a topic within theoretical discussions of high-valent iron chemistry. It serves as a reference point for the limits of iron oxidation states and the challenges involved in stabilizing iron in the highest conceivable oxo-oxide configurations.

See also: ferrate, ferrate(VI)