What is "polyoxometalate"

alt. (context chemistry English) Any of several metallates containing cluster of transition metal atoms ligated to oxygen and other atoms; they are either synthetic or occur naturally as minerals n. (context chemistry English) Any of several metallates containing cluster of transition metal atoms ligated to oxygen and other atoms; they are either synthetic or occur naturally as minerals

In chemistry, a polyoxometalate (abbreviated POM) is a polyatomic ion, usually an anion, that consists of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks. The metal atoms are usually group 6 (Mo, W) or less commonly group 5 (V, Nb, Ta) transition metals in their high oxidation states. They are usually colorless or orange, diamagnetic anions. Two broad families are recognized, isopolymetalates, composed of only one kind of metal and oxide, and heteropolymetalates, composed of one metal, oxide, and a main group oxyanion ( phosphate, silicate, etc). Many exceptions to these general statements exist.