In
inorganic nomenclature, a
manganate is any negatively charged
molecular entity with
manganese as the central atom. However, the name is usually used to refer to the
tetraoxidomanganate(2-) anion, MnO, also known as
manganate(VI) because it contains manganese in the +6
oxidation state. Manganates are the only known manganese(VI) compounds.