Calcium phosphate is the name given to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. They are white solids of nutritious value.
Orthophosphates, di- and monohydrogen phosphates
These materials contain Ca2+ combined with PO43−, HPO42−, and/or H2PO4−:
Di- and polyphosphates
These materials contain Ca2+ combined with the polyphosphates, such as P2O74− and triphosphate [P3O10]5−:
Hydroxy- and oxo-phosphates
These materials contain other anions in addition to phosphate:
Calcium phosphates are found in many living organisms, e.g., bone mineral) and tooth enamel. In milk, it exists in a colloidal form in micelles bound to casein protein with magnesium, zinc, and citrate - collectively referred to as colloidal calcium phosphate (CCP). Various calcium phosphate minerals are used in the production of phosphoric acid and fertilizers. Overuse of certain forms of calcium phosphate can lead to nutrient-containing surface runoff and subsequent adverse effects upon receiving waters such as algal blooms and eutrophication.