焦磷酸钙，化学式Ca₂P₂O₇。

焦磷酸钙是一种白色粉末，不溶于水和醇，溶于稀盐酸和硝酸，水悬浮液呈酸性。根据温度不同，可有三种不同的晶型：α型（1210 °C）、β型（750～900 °C）和γ型（530～750 °C）。

Calcium pyrophosphate (Ca₂P₂O₇) is a chemical compound, an insoluble calcium salt containing the pyrophosphate anion. There are a number of forms reported: an anhydrous form, a dihydrate, Ca₂P₂O₇·2H₂O and a tetrahydrate, Ca₂P₂O₇·4H₂O. Deposition of dihydrate crystals in cartilage are responsible for the severe joint pain in cases of calcium pyrophosphate deposition disease (pseudo gout) whose symptoms are similar to those of gout. Ca₂P₂O₇ is commonly used as a mild abrasive agent in toothpastes.