Materials Data on Al2SiO5 by Materials Project

Abstract

Al2SiO5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Al3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Al–O bond distances ranging from 1.83–2.19 Å. Si4+ is bonded to six O2- atoms to form corner-sharing SiO6 octahedra. The corner-sharing octahedral tilt angles are 32°. There are a spread of Si–O bond distances ranging from 1.70–1.89 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Al3+ and one Si4+ atom to form distorted OAl3Si trigonal pyramids that share a cornercorner with one OAl2Si2 tetrahedra, corners with three equivalent OAl3Si trigonal pyramids, edges with two equivalent OAl2Si2 tetrahedra, and edges with two equivalent OAl3Si trigonal pyramids. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Al3+ and one Si4+ atom. In the third O2- site, O2- is bonded to two equivalent Al3+ and two equivalent Si4+ atoms to form distorted OAl2Si2 tetrahedra that share corners with two equivalent OAl2Si2 tetrahedra, corners with two equivalent OAl3Si trigonal pyramids, and edges with four equivalent OAl3Si trigonal pyramids.