The Collaborative International Dictionary
Pyrophosphoric
Pyrophosphoric \Pyr`o*phos*phor"ic\, a. [Pyro- + phosphoric.] (Chem.) Pertaining to, or designating, an acid, H4P2O7, which is obtained as a white crystalline substance. Its salts are obtained by heating the phosphates.
Wiktionary
pyrophosphoric
a. of, or relating to pyrophosphoric acid or its derivatives