Monocalcium phosphate

Source: Wikipedia, the free encyclopedia.
Monocalcium phosphate
Names
IUPAC name
Calcium bis(dihydrogen phosphate)
Other names
Acid calcium phosphate
Calcium acid phosphate
Calcium diorthophosphate
Calcium biphosphate
Calcium superphosphate
Monobasic calcium phosphate
Monocalcium orthophosphate
Phosphoric acid, calcium salt (2:1)
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.028.943 Edit this at Wikidata
E number E341(i) (antioxidants, ...)
UNII
  • InChI=1S/Ca.2H3O4P/c;2*1-5(2,3)4/h;2*(H3,1,2,3,4)/q+2;;/p-2 ☒N
    Key: YYRMJZQKEFZXMX-UHFFFAOYSA-L ☒N
  • InChI=1/Ca.2H3O4P/c;2*1-5(2,3)4/h;2*(H3,1,2,3,4)/q+2;;/p-2
    Key: YYRMJZQKEFZXMX-NUQVWONBAY
  • OP(=O)(O)[O-].OP(=O)(O)[O-].[Ca+2]
Properties
CaH4P2O8
Molar mass 234.05 g/mol
Appearance White powder
Density 2.220 g/cm3
Melting point 109 °C (228 °F; 382 K)
Boiling point 203 °C (397 °F; 476 K) (decomposes)
2 g/100 mL
1.5176
Structure
Triclinic
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point Non-flammable
Related compounds
Other anions
 Calcium pyrophosphate
Other cations
 Magnesium phosphate
Dicalcium phosphate
Tricalcium phosphate
Strontium phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Monocalcium phosphate is an

monohydrate ("MCP" or "MCP-M"), Ca(H2PO4)2·H2O. Both salts are colourless solids. They are used mainly as superphosphate fertilizers and are also popular leavening agents.[1]

Preparation

Material of relatively high purity, as required for baking, is produced by treating calcium hydroxide with phosphoric acid:

Ca(OH)2 + 2 H3PO4 → Ca(H2PO4)2 + 2 H2O

Samples of Ca(H2PO4)2 tend to convert to dicalcium phosphate:

Ca(H2PO4)2 → Ca(HPO4) + H3PO4

Applications

Use in fertilizers

phosphate rock" with acids ("acidulation"). Using phosphoric acid, fluorapatite
is converted to Ca(H2PO4)2:

Ca5(PO4)3F + 7 H3PO4 → 5 Ca(H2PO4)2 + HF

This solid is called

triple superphosphate. Several million tons are produced annually for use as fertilizers
. Using sulfuric acid, fluorapatite is converted to a mixture of Ca(H2PO4)2 and CaSO4. This solid is called
single superphosphate
.

Residual HF typically reacts with silicate minerals co-mingled with the phosphate ores to produce hexafluorosilicic acid (H2SiF6). The majority of the hexafluorosilicic acid is converted to aluminium fluoride and cryolite for the processing of aluminium.[1] These materials are central to the conversion of aluminium ore into aluminium metal.

When sulfuric acid is used, the product contains phosphogypsum (CaSO4·2H2O) and is called single superphosphate. [2]

Use as leavening agent

Calcium dihydrogen phosphate is used in the food industry as a

sodium acid pyrophosphate (SAPP).[3]

See also

References

  1. ^
    ISBN 978-3527306732
    .
  2. ISBN 978-3527306732
    .
  3. doi:10.1002/0471238961.0308051303082114.a01.pub2

Further reading
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