Cr2AlN3 crystallizes in the orthorhombic Cmcm space group. Cr(1) is bonded to one N(2) and four equivalent N(1) atoms to form CrN5 trigonal bipyramids that share corners with three equivalent Al(1)N5 trigonal bipyramids, corners with five equivalent Cr(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N5 trigonal bipyramids, and edges with four equivalent Cr(1)N5 trigonal bipyramids. Al(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form AlN5 trigonal bipyramids that share corners with two equivalent Al(1)N5 trigonal bipyramids, corners with six equivalent Cr(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N5 trigonal bipyramids, and edges with four equivalent Cr(1)N5 trigonal bipyramids. There are two inequivalent N sites. In the first N site, N(2) is bonded to two equivalent Cr(1) and three equivalent Al(1) atoms to form NAl3Cr2 trigonal bipyramids that share corners with two equivalent N(2)Al3Cr2 trigonal bipyramids, corners with six equivalent N(1)AlCr4 trigonal bipyramids, edges with two equivalent N(2)Al3Cr2 trigonal bipyramids, and edges with four equivalent N(1)AlCr4 trigonal bipyramids. In the second N site, N(1) is bonded to four equivalent Cr(1) and one Al(1) atom to form NAlCr4 trigonal bipyramids that share corners with three equivalent N(2)Al3Cr2 trigonal bipyramids, corners with five equivalent N(1)AlCr4 trigonal bipyramids, edges with two equivalent N(2)Al3Cr2 trigonal bipyramids, and edges with four equivalent N(1)AlCr4 trigonal bipyramids.
Cr2AlN3 crystallizes in the orthorhombic Cmcm space group. Cr(1) is bonded to one N(2) and four equivalent N(1) atoms to form CrN5 trigonal bipyramids that share corners with three equivalent Al(1)N5 trigonal bipyramids, corners with five equivalent Cr(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N5 trigonal bipyramids, and edges with four equivalent Cr(1)N5 trigonal bipyramids. The Cr(1)-N(2) bond length is 2.12 Å. There are two shorter (1.92 Å) and two longer (1.99 Å) Cr(1)-N(1) bond lengths. Al(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form AlN5 trigonal bipyramids that share corners with two equivalent Al(1)N5 trigonal bipyramids, corners with six equivalent Cr(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N5 trigonal bipyramids, and edges with four equivalent Cr(1)N5 trigonal bipyramids. Both Al(1)-N(1) bond lengths are 1.90 Å. There is one shorter (1.93 Å) and two longer (1.97 Å) Al(1)-N(2) bond lengths. There are two inequivalent N sites. In the first N site, N(2) is bonded to two equivalent Cr(1) and three equivalent Al(1) atoms to form NAl3Cr2 trigonal bipyramids that share corners with two equivalent N(2)Al3Cr2 trigonal bipyramids, corners with six equivalent N(1)AlCr4 trigonal bipyramids, edges with two equivalent N(2)Al3Cr2 trigonal bipyramids, and edges with four equivalent N(1)AlCr4 trigonal bipyramids. In the second N site, N(1) is bonded to four equivalent Cr(1) and one Al(1) atom to form NAlCr4 trigonal bipyramids that share corners with three equivalent N(2)Al3Cr2 trigonal bipyramids, corners with five equivalent N(1)AlCr4 trigonal bipyramids, edges with two equivalent N(2)Al3Cr2 trigonal bipyramids, and edges with four equivalent N(1)AlCr4 trigonal bipyramids.