Materials Data on Al4Fe(SiO6)2 by Materials Project
FeAl4(SiO6)2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Fe is bonded to four O atoms to form FeO4 tetrahedra that share corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There is two shorter (1.87 Å) and two longer (1.99 Å) Fe–O bond length. 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 FeO4 tetrahedra, corners with four equivalent SiO4 tetrahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.93 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent SiO4 tetrahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–1.98 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with seven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are five inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to two Al and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the third O site, O is bonded in a distorted trigonal planar geometry to two equivalent Al and one Si atom. In the fourth O site, O is bonded to one Fe and three Al atoms to form distorted corner-sharing OAl3Fe trigonal pyramids. In the fifth O site, O is bonded in a trigonal planar geometry to one Fe and two equivalent Al atoms.