Calcium pyrophosphate Ca₂P₂O₇ is a chemical compound that can be formed by the reaction of Pyrophosphoric acid and a calcium base or by strongly heating calcium hydrogen orthophosphate or calcium ammonium orthophosphate.

Specific gravity 3.09 Melting point 1230C. Insoluble in cold water. It is commonly used as a mild abrasive agent in toothpastes.

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