Disodium pyrophosphate 酸式焦磷酸钠
（重定向自Sodium Acid Pyrophosphate）
Disodium pyrophosphate or sodium acid pyrophosphate is an inorganic compound consisting of sodium cations and pyrophosphate anion. It is a white, water-soluble solid that serves as a buffering and chelating agent, with many applications in the food industry. When crystallised from water, it forms a hexahydrate, but it dehydrates above room temperature. Pyrophosphate is a polyvalent anion with a high affinity for polyvalent cations, e.g. Ca.