Materials Data on Al2O3 by Materials Project

Al2O3 is beta indium sulfide-like structured and 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 four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–61°. There is one shorter (1.80 Å) and three longer (1.81 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent AlO6 octahedra, corners with two equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. The corner-sharing octahedra tilt angles range from 9–20°. There are a spread of Al–O bond distances ranging from 1.85–2.14 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra and edges with seven AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.08 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra and edges with seven AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.05 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedra tilt angles range from 10–15°. There are a spread of Al–O bond distances ranging from 1.96–2.01 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra and edges with eight AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.97 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent AlO6 octahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. The corner-sharing octahedra tilt angles range from 10–11°. There are a spread of Al–O bond distances ranging from 1.89–2.06 Å. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Al–O bond distances ranging from 1.77–1.82 Å. In the ninth 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 1.77–1.87 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra and edges with eight AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.96 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent AlO6 octahedra, corners with three equivalent AlO4 tetrahedra, and edges with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 13–15°. There are a spread of Al–O bond distances ranging from 1.83–2.20 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra and edges with eight AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.98 Å. In the thirteenth Al3+ site, Al3+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Al–O bond distances ranging from 1.72–2.47 Å. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing AlO6 octahedra. The corner-sharing octahedra tilt angles range from 9–20°. There are a spread of Al–O bond distances ranging from 1.90–2.14 Å. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.78–2.25 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form edge-sharing AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.09 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four 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 distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to four Al3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to four 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 rectangular see-saw-like geometry to four Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the seventeenth O2- site, O2- is bonded to four Al3+ atoms to form corner-sharing OAl4 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to four Al3+ atoms to form distorted corner-sharing OAl4 tetrahedra. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-first O2- site, O2- is bonded in a water-like geometry to two Al3+ atoms. In the twenty-second O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Al3+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted T-shaped geometry to three Al3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to four Al3+ atoms.