CaCo3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted CaO7 pentagonal bipyramids that share corners with six equivalent Co(1)O5 trigonal bipyramids and edges with two equivalent Co(1)O5 trigonal bipyramids. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted CoO5 trigonal bipyramids that share corners with three equivalent Ca(1)O7 pentagonal bipyramids,  an edgeedge with one Ca(1)O7 pentagonal bipyramid, and edges with two equivalent Co(1)O5 trigonal bipyramids. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Co(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Co(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Co(2), and two equivalent Co(1) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Co(2), and two equivalent Co(1) atoms.
CaCo3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted CaO7 pentagonal bipyramids that share corners with six equivalent Co(1)O5 trigonal bipyramids and edges with two equivalent Co(1)O5 trigonal bipyramids. The Ca(1)-O(3) bond length is 2.36 Å. Both Ca(1)-O(1) bond lengths are 2.48 Å. Both Ca(1)-O(2) bond lengths are 2.55 Å. Both Ca(1)-O(4) bond lengths are 2.32 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted CoO5 trigonal bipyramids that share corners with three equivalent Ca(1)O7 pentagonal bipyramids,  an edgeedge with one Ca(1)O7 pentagonal bipyramid, and edges with two equivalent Co(1)O5 trigonal bipyramids. The Co(1)-O(4) bond length is 1.66 Å. There is one shorter (1.91 Å) and one longer (1.92 Å) Co(1)-O(1) bond length. There is one shorter (1.91 Å) and one longer (1.92 Å) Co(1)-O(2) bond length. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. The Co(2)-O(3) bond length is 1.67 Å. Both Co(2)-O(1) bond lengths are 1.97 Å. Both Co(2)-O(2) bond lengths are 1.97 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Co(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Co(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Co(2), and two equivalent Co(1) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Co(2), and two equivalent Co(1) atoms.