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|Section2= |Section3= |Section7= |Section8= }} Dicalcium phosphate is a misnomer for dibasic calcium phosphate. Its chemical formula is CaHPO4. Hence the name "dicalcium" is incorrect. The correct names of this material are dibasic calcium phosphate or calcium monohydrogen phosphate. There are three crystalline forms: a dihydrate, CaHPO4•2H2O ('DPCD'), the mineral brushite; a hemihydrate, CaHPO4•0.5H2O; and anhydrous CaHPO4 ('DCPA'), the mineral monetite. Below pH 4.8 the dihydrate and anhydrous forms of dibasic calcium phosphate are the most stable (insoluble) of the calcium phosphates. Dibasic calcium phosphate is used as a food additive, it is found in some toothpastes as a polishing agent and is a biomaterial. In the dihydrate (brushite) form it is found in some kidney stones and in dental calculi.〔 〕〔 〕 ==Preparation== Dibasic calcium phosphate is produced by the reaction of calcium chloride and phosphoric acid: :CaCl2 + H3PO4 + 2 NaOH → CaHPO4 + 2 NaCl + 2 H2O Calcium hydroxide is also used in place of the calcium chloride and sodium hydroxide. The room temperature neutralisation of phosphoric acid with calcium hydroxide at pH 3-4 precipitates the dihydrate. At 60°C the anhydrous form is precipitated:〔 :H3PO4 + Ca(OH)2 → CaHPO4 One industrial preparation of the dihydrate involves the reaction of H3PO4 with a slurry of Ca(OH)2 below 40°C. To prevent degradation that would form hydroxyapatite, Sodium pyrophosphate or trimagnesium phosphate octahydrate are added when for example, dibasic calcium phosphate dihydrate is to be used as a polishing agent in toothpaste.〔 Anhydrous CaHPO4 is an intermediate in the production of halophosphate phosphors that were used in fluorescent lamps. In a continuous process CaCl2 was reacted with (NH4)2HPO4 to form the dihydrate, CaHPO4•2H2O. :CaCl2 + (NH4)2HPO4 → CaHPO4•2H2O A slurry of the dihydrate is then heated to around 65–70°C to form anhydrous CaHPO4 as a crystalline precipitate in the desired form, (typically a flat diamond shaped crystal, 7-9 μm), which was suitable for further processing. Dibasic calcium phosphate dihydrate is formed in "brushite" calcium phosphate cements (CPC's) which have medical applications. An example of the overall setting reaction in the formation of "β-TCP/MCPM" (β-tricalcium phosphate/monocalcium phosphate) calcium phosphate cements is:〔 〕 :Ca3(PO4)2 + Ca(H2PO4)2•H2O + 7 H2O → 4 CaHPO4•2H2O 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「dicalcium phosphate」の詳細全文を読む スポンサード リンク
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