Ferrate
Ferrate loosely refers to a material that can be viewed as containing anionic iron complexes. The term ferrate derives.
Examples include tetrachloroferrate, oxyanions, and the organoferrates, including highly reduced tetracarbonylferrate salts. Although rarely studied, ferrate 3− and ferrate 4− oxyanions of iron also exist. These too are called ferrates.
Ferrate(VI) is a strong oxidizer, used in water purification and battery technology.