Dicalcium phosphate
<templatestyles src="Chembox/styles.css"/>
Template:Chembox image cellTemplate:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox SolubilityInWaterTemplate:Chembox headerbarTemplate:Chembox headerbarTemplate:Chembox headerbarTemplate:Chembox Datapage checkTemplate:Chembox Footer| Template:Longitem | Template:Unbulleted list |
| ChEBI | Template:Unbulleted list |
| ChemSpider | Template:Unbulleted list |
| DrugBank | Template:Unbulleted list |
| EC Number | Template:Unbulleted list |
| KEGG | Template:Unbulleted list |
| Template:Longitem | Template:Unbulleted list |
| RTECS number | Template:Unbulleted list |
| Script error: No such module "collapsible list". | |
| Script error: No such module "collapsible list". | |
| Template:Longitem | CaHPO4 |
| Molar mass | 136.06 g/mol (anhydrous) 172.09 (dihydrate) |
| Appearance | white powder |
| Odor | odorless |
| Density | 2.929 g/cm3 (anhydrous) 2.31 g/cm3 (dihydrate) |
| Melting point | Template:Chembox CalcTemperatures |
| Template:Longitem | triclinic |
| NFPA 704 (fire diamond) | Template:NFPA 704 diamond |
| Flash point | Template:Chembox CalcTemperatures |
| Template:Longitem | Calcium pyrophosphate |
| Template:Longitem | Magnesium phosphate Monocalcium phosphate Tricalcium phosphate Strontium phosphate |
Template:Chembox Footer/trackingScript error: No such module "TemplatePar".Template:Short description
Dicalcium phosphate is the calcium phosphate with the formula CaHPO4 and its dihydrate. The "di" prefix in the common name arises because the formation of the HPO42– anion involves the removal of two protons from phosphoric acid, H3PO4. It is also known as dibasic calcium phosphate or calcium monohydrogen phosphate. Dicalcium phosphate is used as a food additive, and it is found in some toothpastes as a polishing agent and biomaterial.[1][2]
Preparation
Dibasic calcium phosphate is produced by neutralizing calcium hydroxide with phosphoric acid, precipitating the dihydrate as a solid. At 60 °C the anhydrous form is precipitated:[3] Template:Block indent
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.[1]
In a continuous process CaCl2 can be treated with (NH4)2HPO4 to form the dihydrate: Template:Block indent A slurry of the dihydrate is then heated to around 65–70 °C to form anhydrous CaHPO4 as a crystalline precipitate, typically as flat diamondoid crystals, which are suitable for further processing.Script error: No such module "Unsubst".
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:[4] Template:Block indent
2portion.jpg){kind=link}
Structure
Three forms of dicalcium phosphate are known:
- dihydrate, CaHPO4•2H2O ('DCPD'), the mineral brushite
- monohydrate, CaHPO4•H2O ('DCPM')
- anhydrous CaHPO4 ('DCPA'), the mineral monetite. Below pH 4.8, the dihydrate and anhydrous forms of dicalcium phosphate are the most stable (insoluble) calcium phosphates.
The structure of the anhydrous and dihydrated forms has been determined by X-ray crystallography, and the structure of the monohydrate was determined by electron crystallography. The dihydrate[5] (shown in table above) as well as the monohydrate,[6] adopt layered structures.
Uses and occurrence
Dibasic calcium phosphate is mainly used as a dietary supplement in prepared breakfast cereals, dog treats, enriched flour, and noodle products. It is also used as a tableting agent in some pharmaceutical preparations, including some products meant to eliminate body odor. Dibasic calcium phosphate is also found in some dietary calcium supplements (e.g., Bonexcin). It is used in poultry feed. It is also used in some toothpastes as a tartar control agent.[7]
Heating dicalcium phosphate gives dicalcium diphosphate, a useful polishing agent: Template:Block indent
In the dihydrate (brushite) form, it is found in some kidney stones and dental calculi.[8][3]
See also
References
<templatestyles src="Reflist/styles.css" />
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
Script error: No such module "Check for unknown parameters".
Script error: No such module "Navbox". Template:Phosphates