|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
Manganese violet is the inorganic compound called ammonium manganese(III) pyrophosphate. The formula indicates that pyrophosphate (P2O74-), ammonium (NH4+), and manganese(IIII) comprise this solid. It is prepared by heating a mixture of Mn2O3, diammonium phosphate and phosphoric acid. This material is a popular inorganic pigment.
Two polymorphs are known, referred to as the α- and β-forms, but in each case the structures are similar. The Mn(III) centres occupy distorted octahedral sites, being surrounded by six oxygens provided by the pyrophosphate ligands.
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- Yasmin Begum, Adrian J. Wright "Relating highly distorted Jahn–Teller MnO6 to colouration in manganese violet pigments" J. Mater. Chem., 2012, vol. 22, pp. 21110–21116. doi:10.1039/c2jm33731b