Manganese violet

Manganese violet

Names
Other names ammonium manganese(III) pyrophosphate
Identifiers
CAS Number	10101-66-3
Properties
Chemical formula	NH4MnP2O7
Molar mass	246.885
Appearance	violet solid
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Manganese violet is the inorganic compound called ammonium manganese(III) pyrophosphate. The formula indicates that pyrophosphate (P
₂O⁴⁻
₇), ammonium (NH⁺
₄), and manganese(III) make up this solid. It is prepared by heating a mixture of Mn
₂O
₃, diammonium phosphate and phosphoric acid. This material is a popular inorganic pigment.

Chemical structure

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.