Materials Data on Al2O3 by Materials Project

Abstract

Al2O3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 19°. There are a spread of Al–O bond distances ranging from 1.86–1.97 Å. In the second 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 1.78–2.42 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing AlO6 octahedra. The corner-sharing octahedra tilt angles range from 19–52°. There are a spread of Al–O bond distances ranging from 1.93–1.97 Å. In the fourth 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 1.79–2.41 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Al–O bond distances ranging from 1.79–2.01 Å. In the sixth 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 1.78–2.30 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to five Al3+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the 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 fourth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of edge and corner-sharing OAl4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to five Al3+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to five Al3+ atoms. In the eighth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of edge and corner-sharing OAl4 trigonal pyramids.