CoAlO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Al(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with eight equivalent Al(1)O4 tetrahedra and edges with three equivalent Co(1)O6 octahedra. Al(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra, corners with four equivalent Co(2)O6 octahedra, and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Co(2), two equivalent Co(1), and one Al(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one Al(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Al(1) atoms.
CoAlO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with six equivalent Al(1)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with three equivalent Co(2)O6 octahedra. Both Co(1)-O(2) bond lengths are 1.93 Å. There are two shorter (1.95 Å) and two longer (1.97 Å) Co(1)-O(1) bond lengths. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with eight equivalent Al(1)O4 tetrahedra and edges with three equivalent Co(1)O6 octahedra. Both Co(2)-O(1) bond lengths are 2.08 Å. Both Co(2)-O(2) bond lengths are 1.92 Å. Both Co(2)-O(3) bond lengths are 2.04 Å. Al(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra, corners with four equivalent Co(2)O6 octahedra, and corners with two equivalent Al(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. The Al(1)-O(1) bond length is 1.82 Å. The Al(1)-O(2) bond length is 1.78 Å. There is one shorter (1.76 Å) and one longer (1.77 Å) Al(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Co(2), two equivalent Co(1), and one Al(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one Al(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Al(1) atoms.