Ca(CoO2)4 crystallizes in the monoclinic Cm space group. Ca(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. In the second Co site, Co(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. In the third Co site, Co(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. In the fourth Co site, Co(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(3) and two equivalent Co(4) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Co(1), and two equivalent Co(3) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Co(4), and two equivalent Co(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Co(1) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Co(4), and two equivalent Co(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Co(3), and two equivalent Co(2) atoms to form a mixture of distorted corner and edge-sharing OCa2Co3 trigonal bipyramids. In the seventh O site, O(7) is bonded to two equivalent Ca(1), one Co(1), and two equivalent Co(4) atoms to form a mixture of distorted corner and edge-sharing OCa2Co3 trigonal bipyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Co(2), and two equivalent Co(3) atoms.
Ca(CoO2)4 crystallizes in the monoclinic Cm space group. Ca(1) is bonded in a 10-coordinate geometry to one O(2), one O(3), two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms. The Ca(1)-O(2) bond length is 2.61 Å. The Ca(1)-O(3) bond length is 2.62 Å. Both Ca(1)-O(5) bond lengths are 2.81 Å. Both Ca(1)-O(6) bond lengths are 2.52 Å. Both Ca(1)-O(7) bond lengths are 2.56 Å. Both Ca(1)-O(8) bond lengths are 2.77 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Co(1)-O(2) bond length is 1.85 Å. The Co(1)-O(7) bond length is 1.94 Å. Both Co(1)-O(4) bond lengths are 1.86 Å. Both Co(1)-O(5) bond lengths are 1.94 Å. In the second Co site, Co(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Co(2)-O(4) bond length is 1.77 Å. The Co(2)-O(8) bond length is 1.90 Å. Both Co(2)-O(3) bond lengths are 1.88 Å. Both Co(2)-O(6) bond lengths are 1.96 Å. In the third Co site, Co(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Co(3)-O(1) bond length is 1.77 Å. The Co(3)-O(6) bond length is 1.91 Å. Both Co(3)-O(2) bond lengths are 1.89 Å. Both Co(3)-O(8) bond lengths are 1.94 Å. In the fourth Co site, Co(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Co(4)-O(3) bond length is 1.86 Å. The Co(4)-O(5) bond length is 1.92 Å. Both Co(4)-O(1) bond lengths are 1.86 Å. Both Co(4)-O(7) bond lengths are 1.96 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(3) and two equivalent Co(4) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Co(1), and two equivalent Co(3) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Co(4), and two equivalent Co(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Co(1) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Co(4), and two equivalent Co(1) atoms. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Co(3), and two equivalent Co(2) atoms to form a mixture of distorted corner and edge-sharing OCa2Co3 trigonal bipyramids. In the seventh O site, O(7) is bonded to two equivalent Ca(1), one Co(1), and two equivalent Co(4) atoms to form a mixture of distorted corner and edge-sharing OCa2Co3 trigonal bipyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Co(2), and two equivalent Co(3) atoms.