Calcium pyrophosphate

Calcium pyrophosphate
	IUPAC name Calcium diphosphate
Other names Diphosphoric acid, calcium salt (1:2)
Identifiers
CAS number	7790-76-3 Y
PubChem	24632
ChemSpider	23034 Y
UNII	X69NU20D19 Y
MeSH	Calcium+pyrophosphate
ChEBI	CHEBI:32598 Y
Jmol-3D images	{{#if:[Ca+2].[Ca+2].[O-]P([O-])(=O)OP([O-])([O-])=O|Image 1
SMILES [Ca+2].[Ca+2].[O-]P([O-])(=O)OP([O-])([O-])=O
InChI InChI=1S/2Ca.H4O7P2/c;;1-8(2,3)7-9(4,5)6/h;;(H2,1,2,3)(H2,4,5,6)/q2*+2;/p-4 Y Key: JUNWLZAGQLJVLR-UHFFFAOYSA-J Y InChI=1/2Ca.H4O7P2/c;;1-8(2,3)7-9(4,5)6/h;;(H2,1,2,3)(H2,4,5,6)/q2*+2;/p-4 Key: JUNWLZAGQLJVLR-XBHQNQODAN
Properties
Molecular formula	Ca2O7P2
Molar mass	254.053 g/mol
Appearance	white powder
Density	3.09 g/cm3
Melting point	1,353 °C; 2,467 °F; 1,626 K
Solubility in water	insoluble
Solubility	soluble in HCl, nitric acids
Refractive index (nD)	1.585
Hazards
EU Index	Not listed
NFPA 704	0 2 0
Flash point	Non-flammable
Related compounds
Other anions	Calcium phosphate
Other cations	Magnesium pyrophosphate Sodium pyrophosphate
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Calcium pyrophosphate (Ca₂P₂O₇) is a chemical compound that can be formed by the reaction of pyrophosphoric acid and a calcium base or by strongly heating calcium phosphate or calcium ammonium phosphate.

It is commonly used as a mild abrasive agent in toothpastes.

Deposition of CPPD in articular joints causes an arthritis condition called pseudogout.

See also

• Calcium pyrophosphate deposition disease

Calcium pyrophosphate crystals deposited in the cartilage is responsible for the severe joint pain in cases of pseudogout whose symtoms are similar to those of gout. Pseudogout is not related to diet. In the case of gout, which is associated with diet,the pain is caused by the needle-like uric acid crystals in the joint.