Metallate or metalate is the name given to any complex anion containing a metal ligated to several atoms or small groups.
Typically, the metal will be one of the transition elements and the ligand will be oxygen or another chalcogenide or a cyanide group (though others are known). The chalcogenide metallates are known as oxometallates, thiometallates, selenometallates and tellurometallates; the cyanide metallates are known as cyanometallates.
Oxometallates include
permanganate (MnO−
4),
chromate (CrO2−
4) and
vanadate (VO−
3 or VO3−
4).
Thiometallates include
tetrathiovanadate (VS3−
4),
tetrathiomolybdate (MoS2−
4),
tetrathiotungstate (WS2−
4) and similar ions.
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Cyanometallates include ferricyanide and ferrocyanide.
Metallate is also used as a verb by bioinorganic chemistry to describe the act of adding metal atoms or ions to a site (synthetic ligand or protein).