Materials Data on Al2SiO5 by Materials Project

Abstract

Al2SiO5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with three equivalent SiO6 octahedra, corners with four equivalent AlO6 octahedra, an edgeedge with one AlO6 octahedra, edges with two equivalent SiO6 octahedra, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 42–59°. There are a spread of Al–O bond distances ranging from 1.80–2.09 Å. Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with six equivalent AlO6 octahedra, and edges with four equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 42–56°. There are a spread of Si–O bond distances ranging from 1.76–1.90 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Al3+ and two equivalent Si4+ atoms to form distorted OAl2Si2 trigonal pyramids that share corners with four OAl2Si2 trigonal pyramids and edges with four equivalent OAl3Si trigonal pyramids. In the second O2- site, O2- is bonded to three equivalent Al3+ and one Si4+ atom to form a mixture of distorted corner and edge-sharing OAl3Si trigonal pyramids. In the third O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Al3+ and one Si4+ atom.