DOI: 10.17188/1288819
title: Materials Data on Al2O3 by Materials Project

description: Al2O3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra, corners with two equivalent AlO5 square pyramids, and an edgeedge with one AlO5 square pyramid. The corner-sharing octahedra tilt angles range from 14–71°. There are a spread of Al–O bond distances ranging from 1.75–1.84 Å. In the second Al3+ site, Al3+ is bonded to five O2- atoms to form distorted AlO5 square pyramids that share corners with six AlO6 octahedra, a cornercorner with one AlO5 square pyramid, corners with two equivalent AlO4 tetrahedra, and an edgeedge with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of Al–O bond distances ranging from 1.81–2.01 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra, an edgeedge with one AlO6 octahedra, and edges with three AlO5 square pyramids. There are a spread of Al–O bond distances ranging from 1.86–2.23 Å. In the fourth Al3+ site, Al3+ is bonded to five O2- atoms to form AlO5 square pyramids that share a cornercorner with one AlO5 square pyramid, corners with three AlO4 tetrahedra, edges with three AlO6 octahedra, and an edgeedge with one AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.82–1.93 Å. In the fifth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with ten AlO6 octahedra and a cornercorner with one AlO5 square pyramid. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Al–O bond distances ranging from 1.80–1.84 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO5 square pyramids, corners with four AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.00 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra, edges with four AlO6 octahedra, and an edgeedge with one AlO5 square pyramid. There are a spread of Al–O bond distances ranging from 1.83–2.06 Å. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with eight AlO6 octahedra and corners with two equivalent AlO5 square pyramids. The corner-sharing octahedra tilt angles range from 51–60°. There are a spread of Al–O bond distances ranging from 1.76–1.84 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO5 square pyramids, corners with four AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.07 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO5 square pyramids, corners with four AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.01 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded in a T-shaped geometry to three Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a tetrahedral geometry to four Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms.