Metaphosphate

A metaphosphate ion is an oxyanion that has the empirical formula PO⁻
₃.^[1] It was first postulated in 1955^[2] but was not observed until 1979, when it was detected by mass spectrometry.^[3] Metaphosphate is an intermediate in the hydrolysis of phosphate esters but it is difficult to isolate, as it readily hydrolyses to from a dihydrogen phosphate ion ([H
₂PO
₄]⁻
) and tends to self-react in the absence of water to form rings or infinite chains:^[4] These species are also called metaphosphates and are generally stable, with some such as sodium trimetaphosphate being produced on an industrial scale.

Trimetaphosphate is a cyclic trimer formed by the self reaction of metaphosphate ions

Metaphosphates can be used as an alternative of white phosphorus in organic syntheses.^[5]

See also

• Sodium trimetaphosphate
• Sodium hexametaphosphate