Cr2Al2O7 crystallizes in the cubic Fd-3m space group. Cr(1) is bonded to six equivalent O(2) atoms to form distorted corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 61°. Al(1) is bonded in a body-centered cubic geometry to two equivalent O(1) and six equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Al(1) atoms to form OAl4 tetrahedra that share corners with four equivalent O(1)Al4 tetrahedra, corners with twelve equivalent O(2)Al2Cr2 tetrahedra, and edges with six equivalent O(2)Al2Cr2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Cr(1) and two equivalent Al(1) atoms to form OAl2Cr2 tetrahedra that share corners with two equivalent O(1)Al4 tetrahedra, corners with twelve equivalent O(2)Al2Cr2 tetrahedra,  an edgeedge with one O(1)Al4 tetrahedra, and edges with four equivalent O(2)Al2Cr2 tetrahedra.
Cr2Al2O7 crystallizes in the cubic Fd-3m space group. Cr(1) is bonded to six equivalent O(2) atoms to form distorted corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 61°. All Cr(1)-O(2) bond lengths are 1.95 Å. Al(1) is bonded in a body-centered cubic geometry to two equivalent O(1) and six equivalent O(2) atoms. Both Al(1)-O(1) bond lengths are 2.06 Å. All Al(1)-O(2) bond lengths are 2.18 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Al(1) atoms to form OAl4 tetrahedra that share corners with four equivalent O(1)Al4 tetrahedra, corners with twelve equivalent O(2)Al2Cr2 tetrahedra, and edges with six equivalent O(2)Al2Cr2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Cr(1) and two equivalent Al(1) atoms to form OAl2Cr2 tetrahedra that share corners with two equivalent O(1)Al4 tetrahedra, corners with twelve equivalent O(2)Al2Cr2 tetrahedra,  an edgeedge with one O(1)Al4 tetrahedra, and edges with four equivalent O(2)Al2Cr2 tetrahedra.