DOE OSTI2020
Al2O3 is beta indium sulfide-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are twenty-six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.97 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.08 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of Al–O bond distances ranging from 1.76–1.83 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–1.99 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.03 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is one shorter (1.74 Å) and three longer (1.87 Å) Al–O bond length. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.96 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.96 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.02 Å. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is one shorter (1.77 Å) and three longer (1.85 Å) Al–O bond length. In the eleventh Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Al–O bond distances ranging from 1.76–1.83 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.00 Å. In the thirteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.97 Å. In the fourteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of Al–O bond distances ranging from 1.76–1.87 Å. In the fifteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Al–O bond distances ranging from 1.76–1.85 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.02 Å. In the seventeenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.00 Å. In the eighteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.98 Å. In the nineteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–62°. There is one shorter (1.74 Å) and three longer (1.84 Å) Al–O bond length. In the twentieth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There is three shorter (1.76 Å) and one longer (1.86 Å) Al–O bond length. In the twenty-first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.06 Å. In the twenty-second Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Al–O bond distances ranging from 1.76–1.87 Å. In the twenty-third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.01 Å. In the twenty-fourth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of Al–O bond distances ranging from 1.76–1.90 Å. In the twenty-fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–1.96 Å. In the twenty-sixth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Al–O bond distances ranging from 1.77–1.86 Å. There are thirty-six 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 distorted T-shaped geometry to three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fifth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. 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 trigonal planar geometry to three Al3+ atoms. In the eighth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. 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 distorted rectangular see-saw-like geometry to four 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 trigonal planar geometry to three Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fourteenth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twenty-third O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the twenty-fourth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. In the twenty-fifth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the twenty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twenty-seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the thirtieth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the thirty-first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Al3+ atoms. In the thirty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the thirty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the thirty-fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the thirty-fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the thirty-sixth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to four Al3+ atoms.