Co2C2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form corner-sharing CoO4 tetrahedra. In the second Co site, Co(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form corner-sharing CoO4 tetrahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(6) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Co(2) and one C(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Co(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Co(1) and one Co(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Co(2) and one C(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Co(2) and one C(2) atom.
Co2C2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form corner-sharing CoO4 tetrahedra. The Co(1)-O(1) bond length is 1.91 Å. The Co(1)-O(3) bond length is 1.94 Å. The Co(1)-O(4) bond length is 1.79 Å. The Co(1)-O(6) bond length is 1.90 Å. In the second Co site, Co(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form corner-sharing CoO4 tetrahedra. The Co(2)-O(2) bond length is 1.92 Å. The Co(2)-O(4) bond length is 1.79 Å. The Co(2)-O(5) bond length is 1.92 Å. The Co(2)-O(7) bond length is 1.88 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(6) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.29 Å. The C(1)-O(6) bond length is 1.30 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(7) atom. The C(2)-O(3) bond length is 1.29 Å. The C(2)-O(5) bond length is 1.28 Å. The C(2)-O(7) bond length is 1.32 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Co(2) and one C(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Co(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Co(1) and one Co(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Co(2) and one C(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Co(2) and one C(2) atom.