ammonium manganese(III) pyrophosphate
Except where noted otherwise, data is 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(III) make up 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.
- 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
- 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