Cobalt phosphate

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Cobalt phosphate
Cobalt(II) phosphate.JPG
Other names
cobalt violet, cobalt(II) phosphate, cobalt orthophosphate, Pigment Violet 14
(tetrahydrate: 10294-50-5) 13455-36-2 (tetrahydrate: 10294-50-5)
ChemSpider 55523
ECHA InfoCard 100.033.309
EC Number 236-655-6
Jmol 3D model Interactive image
PubChem 61615
Molar mass 366.74231 g/mol
Appearance violet solid
Density 3.81 g/cm3
Melting point 1,160 °C (2,120 °F; 1,430 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Cobalt phosphate is the inorganic compound with the formula Co3(PO4)2. It is a commercial inorganic pigment known as cobalt violet.[1] Thin films of this material catalyze the decomposition of water.[2]

A swatch of cobalt violet, popular among the French impressionists.

Preparation and structure[edit]

It precipitates as a solid tetrahydrate upon mixing aquous solutions of cobalt(II) and phosphate salts. The anhydrous material consists of discrete phosphate (PO3−
) anions that link Co2+

The cobalt ions occupy both octahedral (six-coordinate) and pentacoordinate sites in a 1:2 ratio.[3]

See also[edit]


  1. ^ Hugo Müller, Wolfgang Müller, Manfred Wehner, Heike Liewald "Artists' Colors" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a03_143.pub2
  2. ^ Matthew W. Kanan, Yogesh Surendranatha, Daniel G. Nocera "Cobalt–phosphate oxygen-evolving compound" Chem. Soc. Rev., 2009, volume 38, 109-114. doi:10.1039/B802885K
  3. ^ Anderson, J. B.; Kostiner, E.; Miller, M. C.; Rea, J. R. "Crystal structure of cobalt orthophosphate Co3(PO4)2" Journal of Solid State Chemistry 1975, vol. 14, 372-7.