Materials Data on Al2O3 by Materials Project

Abstract

Al2O3 crystallizes in the trigonal P321 space group. The structure is two-dimensional and consists of one Al2O3 sheet oriented in the (0, 0, 1) direction. there are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded in a 3-coordinate geometry to six O2- atoms. There are three shorter (1.75 Å) and three longer (2.42 Å) Al–O bond lengths. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form a mixture of distorted edge, face, and corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 46°. There is three shorter (1.82 Å) and three longer (2.11 Å) Al–O bond length. 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 46–50°. There is three shorter (1.85 Å) and three longer (2.07 Å) Al–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a 6-coordinate geometry to six Al3+ atoms.