Materials Data on AlCrO3 by Materials Project

Abstract

CrAlO3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Cr3+ is bonded to five O2- atoms to form CrO5 trigonal bipyramids that share corners with six equivalent AlO6 octahedra and corners with six equivalent CrO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 64°. There is three shorter (1.84 Å) and two longer (2.04 Å) Cr–O bond length. Al3+ is bonded to six equivalent O2- atoms to form distorted AlO6 octahedra that share corners with six equivalent CrO5 trigonal bipyramids and edges with six equivalent AlO6 octahedra. All Al–O bond lengths are 2.04 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three equivalent Cr3+ atoms. In the second O2- site, O2- is bonded to one Cr3+ and three equivalent Al3+ atoms to form a mixture of corner and edge-sharing OAl3Cr tetrahedra.