Tribasic calcium phosphate occurs in nature as minerals, oxydapatite, whitlockite, voelicherite, apatite, phosphorite. It has many industrial applications. Some are similar to the monobasic and dibasic salts. It is used in fertilizers, dental products, ceramics and polishing powder. Some other important applications are in plastics as a stabilizer; as an anticaking agent; as a nutrient supplement in cattle food; for clarifying sugar syrup; as a mordant in dyeing textiles; and as a buffer to control pH.
Tribasic calcium phosphate is obtained from naturally occurring minerals for fertilizer applications. The compound may be prepared in the laboratory by the reaction of sodium phosphate with calcium chloride with excess of ammonia. Also, it can be prepared by treatment of calcium hydroxide with phosphoric acid:
2H3PO4 + 3Ca(OH)2 → Ca3(PO4)2 + 6H2O
ChEBI: Tricalcium bis(phosphate) is a calcium phosphate.
Calcium phosphate [Ca3(PO4),] is a white insoluble powder and is the main constituent of bones. Calcium phosphate occurs naturally as rock phosphate in the mineral apatite Ca5(PO4)3,which contains OH-, F- and Cl- ions to a small extent.
Calcium ions and hydrogen phosphate ions react in
the presence of an alkali to produce calcium phosphate.
Calcium phosphate is used extensively as a fertilizer.
Dicalcium phosphate is a common constituent of
nitrophosphate fertilizers and of compound fertilizers
formed by ammoniation of superphosphates. Calcining
of phosphate rock, sodium carbonate and silica in a rotary
kiln at 1250°C gives rhenania, or calcium sodium
phosphate.
