Materials Data on Al2SiO5 by Materials Project

Abstract

Al2SiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent AlO4 tetrahedra, corners with four equivalent SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–62°. There are a spread of Al–O bond distances ranging from 1.72–1.81 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO6 octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms.