Materials Data on MnAl2(SiO5)2 by Materials Project

Abstract

MnAl2(SiO5)2 crystallizes in the orthorhombic Ccce space group. The structure is three-dimensional. Mn is bonded to six O atoms to form MnO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with two equivalent SiO4 tetrahedra, and edges with three equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Mn–O bond distances ranging from 1.91–2.00 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with four equivalent SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Al–O bond distances ranging from 1.91–1.95 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent SiO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with three equivalent MnO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.95 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one MnO6 octahedra, corners with three AlO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–60°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. There are five inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Mn, one Al, and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Mn and one Al atom. In the third O site, O is bonded in a trigonal non-coplanar geometry to one Mn and two equivalent Al atoms. In the fourth O site, O is bonded in a trigonal planar geometry to two equivalent Al and one Si atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to two equivalent Si atoms.