A novel modification of manganese orthophosphate Mn 3(PO 4) 2

Abstract

A new third modification of manganese(II) orthophosphate Mn 3(PO 4) 2 has been obtained under hydrothermal conditions. Its crystal structure was determined by single crystal X-ray diffraction: space group P 2 1 / n , Z = 2 , a = 5.2344 ( 5 ) , b = 6.6739 ( 7 ) , c = 8.9688 ( 10 ) Å , β = 95.276 ( 9 ) ° at 293 K, w R 2 = 0.050 , R = 0.019 . In the structure, [MnO 5] polyhedra and [MnO 6] octahedra in a ratio of 2 : 1 share common edges to form chains alternating along the [110] and [ 1 ¯ 10 ] directions. They are further linked by common vertices and the phosphate tetrahedra to a 3D framework. The relations of this new structure type to the other polymorphs of Mn 3(PO 4) 2 and related Mn and Fe phosphates are discussed.