DOI: 10.17188/1283956
title: Materials Data on Al2O3 by Materials Project

description: Al2O3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to five O2- atoms to form distorted AlO5 square pyramids that share corners with five AlO6 octahedra, a cornercorner with one AlO4 tetrahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–69°. There are a spread of Al–O bond distances ranging from 1.77–2.00 Å. In the second Al3+ site, Al3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Al–O bond distances ranging from 1.79–2.45 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with two equivalent AlO4 tetrahedra, an edgeedge with one AlO6 octahedra, edges with two equivalent AlO5 square pyramids, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Al–O bond distances ranging from 1.85–2.30 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four AlO6 octahedra and corners with three AlO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 47–66°. There are a spread of Al–O bond distances ranging from 1.78–1.82 Å. In the fifth Al3+ site, Al3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.74–1.92 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent AlO6 octahedra, a cornercorner with one AlO4 tetrahedra, corners with two AlO5 trigonal bipyramids, and an edgeedge with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–65°. There are a spread of Al–O bond distances ranging from 1.77–1.91 Å. In the seventh Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra, a cornercorner with one AlO5 square pyramid, and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–67°. There are a spread of Al–O bond distances ranging from 1.74–1.92 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, a cornercorner with one AlO5 square pyramid, corners with four AlO4 tetrahedra, an edgeedge with one AlO6 octahedra, and an edgeedge with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–47°. There are a spread of Al–O bond distances ranging from 1.89–2.06 Å. In the ninth Al3+ site, Al3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.79–1.86 Å. In the tenth Al3+ site, Al3+ is bonded to five O2- atoms to form distorted AlO5 trigonal bipyramids that share a cornercorner with one AlO6 octahedra, corners with two AlO4 tetrahedra, a cornercorner with one AlO5 trigonal bipyramid, an edgeedge with one AlO6 octahedra, and an edgeedge with one AlO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 70°. There are a spread of Al–O bond distances ranging from 1.79–2.04 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four AlO6 octahedra, a cornercorner with one AlO5 trigonal bipyramid, and an edgeedge with one AlO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 38–51°. There are a spread of Al–O bond distances ranging from 1.85–2.11 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with seven AlO4 tetrahedra, a cornercorner with one AlO5 trigonal bipyramid, and an edgeedge with one AlO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 46–47°. There are a spread of Al–O bond distances ranging from 1.85–2.05 Å. In the thirteenth Al3+ site, Al3+ is bonded to five O2- atoms to form AlO5 trigonal bipyramids that share a cornercorner with one AlO6 octahedra, corners with three AlO4 tetrahedra, a cornercorner with one AlO5 trigonal bipyramid, an edgeedge with one AlO6 octahedra, and an edgeedge with one AlO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 61°. There are a spread of Al–O bond distances ranging from 1.83–1.95 Å. In the fourteenth Al3+ site, Al3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.75–1.92 Å. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with two equivalent AlO5 square pyramids, edges with two equivalent AlO6 octahedra, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are a spread of Al–O bond distances ranging from 1.86–2.24 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four AlO6 octahedra, corners with two equivalent AlO5 square pyramids, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 38–55°. There are a spread of Al–O bond distances ranging from 1.83–2.10 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the seventh O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. 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 to four Al3+ atoms to form distorted corner-sharing OAl4 tetrahedra. In the tenth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the eleventh O2- site, O2- is bonded in a distorted T-shaped geometry to three Al3+ atoms. In the twelfth O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to four Al3+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Al3+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Al3+ atoms. In the twentieth O2- site, O2- is bonded to four Al3+ atoms to form distorted corner-sharing OAl4 trigonal pyramids. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to four Al3+ atoms. In the twenty-second O2- site, O2- is bonded to four Al3+ atoms to form a mixture of edge and corner-sharing OAl4 trigonal pyramids. In the twenty-third O2- site, O2- is bonded in a T-shaped geometry to three Al3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to three Al3+ atoms.