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Cobalt phosphate is the 
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemis ...
with the formula Co3(PO4)2. It is a commercial inorganic pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...
known as cobalt violet.Hugo Müller, Wolfgang Müller, Manfred Wehner, Heike Liewald "Artists' Colors" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Thin films of this material are water oxidation catalyst
Water oxidation catalysis (WOC) is the acceleration (catalysis) of the conversion of water into oxygen and protons:
:2 H2O → 4 H+ + 4 e− + O2
Many catalysts are effective, both homogeneous catalysts and heterogeneous catalysts. The oxygen e ...
s.
:
Preparation and structure
The tetrahydrate Co3(PO4)2•4H2O precipitates as a solid upon mixing aqueous solutions of cobalt(II) and phosphate salts. Upon heating, the tetrahydrate converts to the anhydrous material. According toX-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
, the anhydrous Co3(PO4)2 consists of discrete phosphate () anions that link centres. The cobalt ions occupy both octahedral
In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet a ...
(six-coordinate) and pentacoordinate sites in a 1:2 ratio.
See also
*List of inorganic pigments
The following list includes commercially or artistically important inorganic pigments of natural and synthetic origin..
Purple pigments
Aluminum pigments
* Ultramarine violet: (PV15) - a synthetic or naturally occurring sulfur containing silic ...
References
{{Cobalt compounds Phosphates Cobalt(II) compounds Inorganic pigments