Metaphosphate

cyclic trimetaphosphate

A metaphosphate ion is an oxyanion that has the empirical formula PO−
3.^[1] The structure of a metaphosphate ion can be described as being made up of PO₄ structural units in which each unit shares two corners with another unit. This can come about in two ways.

• Formation of a ring, as in trimetaphosphate, illustrated.
• Formation of an infinite chain, with the same structure as in ammonium metavanadate

Metaphosphates can be considered as salts of the corresponding metaphosphoric acids (H_nP_nO_3n) although none of these acids has been isolated. The metaphosphoric acids can be formulated as H₂O·P₂O₅. In comparison, phosphoric acid, H₃PO₄ can be formulated as 3H₂O·P₂O₅ and pyrophosphoric acid, H₄P₂O₇, as 2H₂O·P₂O₅.^[2]

See also

• Sodium trimetaphosphate
• Sodium hexametaphosphate

References

1. Averbuch-Pouchot, M.T; A. Durif, A. (1996). Topics in Phosphate Chemistry. World Scientific Pub Co Inc. ISBN 981-02-2634-9. Cite uses deprecated parameter |coauthors= (help)
2. Corbridge, D. (1995). "Chapter 3: Phosphates". Studies in inorganic Chemistry vol. 20. Elsevier Science B.V. pp. 169–305. ISBN 0-444-89307-5. Retrieved January 30, 2015. – via ScienceDirect (Subscription may be required or content may be available in libraries.)