Materials Data on Al2O3 by Materials Project

Al2O3 is beta indium sulfide-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are five 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 51–60°. There is two shorter (1.77 Å) and two longer (1.83 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 six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.05 Å. In the third 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 1.85–1.99 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–61°. There is two shorter (1.77 Å) and two longer (1.85 Å) Al–O bond length. 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 four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.94 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. 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 distorted rectangular see-saw-like geometry to four 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 in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms.