Ca(Co2O3)2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(4) and four equivalent O(2) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second Co site, Co(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Co(2) and four equivalent Co(1) atoms to form OCo6 octahedra that share corners with four equivalent O(3)Co5 square pyramids, corners with two equivalent O(4)Ca2Co2 tetrahedra, edges with two equivalent O(1)Co6 octahedra, edges with six equivalent O(3)Co5 square pyramids, and edges with four equivalent O(2)Ca2Co3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ca(1), one Co(1), and two equivalent Co(2) atoms to form distorted OCa2Co3 trigonal bipyramids that share corners with five equivalent O(3)Co5 square pyramids, corners with four equivalent O(4)Ca2Co2 tetrahedra, corners with two equivalent O(2)Ca2Co3 trigonal bipyramids, edges with two equivalent O(1)Co6 octahedra,  an edgeedge with one O(3)Co5 square pyramid,  an edgeedge with one O(4)Ca2Co2 tetrahedra, and edges with three equivalent O(2)Ca2Co3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Co(2) and three equivalent Co(1) atoms to form distorted OCo5 square pyramids that share corners with two equivalent O(1)Co6 octahedra, corners with two equivalent O(4)Ca2Co2 tetrahedra, corners with five equivalent O(2)Ca2Co3 trigonal bipyramids, edges with three equivalent O(1)Co6 octahedra, edges with four equivalent O(3)Co5 square pyramids, and  an edgeedge with one O(2)Ca2Co3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 6°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Co(2) atoms to form distorted OCa2Co2 tetrahedra that share corners with two equivalent O(1)Co6 octahedra, corners with four equivalent O(3)Co5 square pyramids, corners with two equivalent O(4)Ca2Co2 tetrahedra, corners with eight equivalent O(2)Ca2Co3 trigonal bipyramids, and edges with two equivalent O(2)Ca2Co3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°.
Ca(Co2O3)2 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(4) and four equivalent O(2) atoms. Both Ca(1)-O(4) bond lengths are 2.26 Å. All Ca(1)-O(2) bond lengths are 2.43 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. The Co(1)-O(2) bond length is 1.84 Å. Both Co(1)-O(1) bond lengths are 2.18 Å. There is one shorter (1.99 Å) and two longer (2.11 Å) Co(1)-O(3) bond lengths. In the second Co site, Co(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. The Co(2)-O(1) bond length is 2.25 Å. The Co(2)-O(4) bond length is 1.94 Å. Both Co(2)-O(2) bond lengths are 2.12 Å. Both Co(2)-O(3) bond lengths are 2.26 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Co(2) and four equivalent Co(1) atoms to form OCo6 octahedra that share corners with four equivalent O(3)Co5 square pyramids, corners with two equivalent O(4)Ca2Co2 tetrahedra, edges with two equivalent O(1)Co6 octahedra, edges with six equivalent O(3)Co5 square pyramids, and edges with four equivalent O(2)Ca2Co3 trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Ca(1), one Co(1), and two equivalent Co(2) atoms to form distorted OCa2Co3 trigonal bipyramids that share corners with five equivalent O(3)Co5 square pyramids, corners with four equivalent O(4)Ca2Co2 tetrahedra, corners with two equivalent O(2)Ca2Co3 trigonal bipyramids, edges with two equivalent O(1)Co6 octahedra,  an edgeedge with one O(3)Co5 square pyramid,  an edgeedge with one O(4)Ca2Co2 tetrahedra, and edges with three equivalent O(2)Ca2Co3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Co(2) and three equivalent Co(1) atoms to form distorted OCo5 square pyramids that share corners with two equivalent O(1)Co6 octahedra, corners with two equivalent O(4)Ca2Co2 tetrahedra, corners with five equivalent O(2)Ca2Co3 trigonal bipyramids, edges with three equivalent O(1)Co6 octahedra, edges with four equivalent O(3)Co5 square pyramids, and  an edgeedge with one O(2)Ca2Co3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 6°. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Co(2) atoms to form distorted OCa2Co2 tetrahedra that share corners with two equivalent O(1)Co6 octahedra, corners with four equivalent O(3)Co5 square pyramids, corners with two equivalent O(4)Ca2Co2 tetrahedra, corners with eight equivalent O(2)Ca2Co3 trigonal bipyramids, and edges with two equivalent O(2)Ca2Co3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°.