Cobalt(II) phosphate
Appearance
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Names | |
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Other names
cobalt violet, cobalt(II) phosphate, cobalt orthophosphate, Pigment Violet 14
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.033.309 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
Co3(PO4)2 | |
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) |
insoluble | |
28,110.0·10−6 cm3/mol | |
Refractive index (nD)
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1.7 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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
The tetrahydrate CoPO4(H2O)4 precipitates as a solid upon mixing aquous solutions of cobalt(II) and phosphate salts. Upon heating, the tetrahydrate converts to the anhydrous material. According to X-ray crystallography, the anhydrous CoPO4 consists of discrete phosphate (PO3−
4) anions that link Co2+
centres. The cobalt ions occupy both octahedral (six-coordinate) and pentacoordinate sites in a 1:2 ratio.[3][4]
See also
References
- ^ 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
- ^ 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
- ^ "Crystal structure of cobalt orthophosphate Co3(PO4)2". Journal of Solid State Chemistry. 14: 372–7. 1975.
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ignored (help) - ^ "Structure of cobalt(II) phosphateStructure refinements of Co3(PO4)2. A Note on the Reliability of Powder Diffraction Studies". Acta Chemica Scandinavica, Series A. 37: 715-p721. 1983.
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