Tags: Chemical Compound, Chemical Substance.
In chemistry the anion the salts and the esters of pyrophosphoric acid are called pyrophosphates. Any salt or ester containing two phosphate groups is called a diphosphate. As a food additive diphosphates are known as E450. As well as the normal pyrophosphates a number of hydrogen pyrophosphates also exist such as Na2H2P2O7.
