noun
1. : an orthophosphate of calcium: as
a. : one of the three simple orthophosphates, white or colorless when pure, usually prepared by reaction of phosphoric acid or phosphorus pentoxide with lime, hydrated lime, or limestone:
(1) : the primary phosphate CaH 4 (PO 4 ) 2 or its monohydrate CaH 4 (PO 4 ) 2 .H 2 O used in the form of superphosphate as a fertilizer and in pure form as an acid ingredient in baking powder, prepared flours, and bakery products — called also calcium dihydrogen phosphate, monobasic calcium phosphate, monocalcium phosphate
(2) : the secondary phosphate CaHPO 4 or its dihydrate CaHPO 4 .2H 2 O found in nature as monetite or brushite respectively and used as a mineral supplement in pharmaceutical preparations and animal feeds and as a polishing agent in tooth powders and pastes — called also calcium hydrogen phosphate, dibasic calcium phosphate, dicalcium phosphate
(3) : the tertiary phosphate Ca 3 (PO 4 ) 2 found in nature as whitlockite and made by fusion of phosphorus pentoxide and lime or by fusion and defluorination of phosphate rock or phosphate sand for use as a fertilizer — called also tribasic calcium phosphate, tricalcium phosphate
b.
(1) : a naturally occurring apatite
(2) : an industrial product consisting essentially of hydroxylapatite usually prepared by adding phosphoric acid to a lime slurry and used chiefly in ceramics, in making enamels and milk glass, as a noncaking agent especially in salt and sugar, and as a source of calcium and phosphorus in pharmaceutical preparations — called also tertiary calcium phosphate, tribasic calcium phosphate, tricalcium phosphate
2. : a phosphate of calcium (as calcium metaphosphate, calcium pyrophosphate) other than an orthophosphate