CrAlO3 crystallizes in the hexagonal P6_3cm space group. Cr(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form CrO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-67°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with six equivalent Cr(1)O5 trigonal bipyramids and edges with three equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Cr(1) atoms. In the third O site, O(3) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. In the fourth O site, O(4) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra.
CrAlO3 crystallizes in the hexagonal P6_3cm space group. Cr(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form CrO5 trigonal bipyramids that share corners with four equivalent Al(1)O6 octahedra and corners with six equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-67°. The Cr(1)-O(2) bond length is 1.86 Å. The Cr(1)-O(3) bond length is 2.01 Å. The Cr(1)-O(4) bond length is 2.03 Å. Both Cr(1)-O(1) bond lengths are 1.86 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with six equivalent Cr(1)O5 trigonal bipyramids and edges with three equivalent Al(1)O6 octahedra. All Al(1)-O(3) bond lengths are 2.00 Å. All Al(1)-O(4) bond lengths are 2.08 Å. In the second Al site, Al(2) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. All Al(2)-O(3) bond lengths are 2.14 Å. All Al(2)-O(4) bond lengths are 1.96 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Cr(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Cr(1) atoms. In the third O site, O(3) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra. In the fourth O site, O(4) is bonded to one Cr(1), one Al(2), and two equivalent Al(1) atoms to form a mixture of edge and corner-sharing OAl3Cr tetrahedra.