CoC5HO4 crystallizes in the monoclinic Cc space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(3), one O(5), and one O(7) atom. The Co(1)-O(1) bond length is 2.14 Å. The Co(1)-O(3) bond length is 2.10 Å. The Co(1)-O(5) bond length is 2.10 Å. The Co(1)-O(7) bond length is 2.05 Å. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(6), and one O(8) atom. The Co(2)-O(1) bond length is 2.01 Å. The Co(2)-O(3) bond length is 2.44 Å. The Co(2)-O(4) bond length is 2.01 Å. The Co(2)-O(6) bond length is 1.96 Å. The Co(2)-O(8) bond length is 2.00 Å. There are ten inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(1), and one O(2) atom. The C(1)-C(5) bond length is 1.49 Å. The C(1)-O(1) bond length is 1.31 Å. The C(1)-O(2) bond length is 1.20 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(3), and one O(4) atom. The C(2)-C(6) bond length is 1.50 Å. The C(2)-O(3) bond length is 1.25 Å. The C(2)-O(4) bond length is 1.29 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(8), one O(5), and one O(6) atom. The C(3)-C(8) bond length is 1.51 Å. The C(3)-O(5) bond length is 1.25 Å. The C(3)-O(6) bond length is 1.26 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(9), one O(7), and one O(8) atom. The C(4)-C(9) bond length is 1.49 Å. The C(4)-O(7) bond length is 1.27 Å. The C(4)-O(8) bond length is 1.26 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(1), one C(10), and one C(6) atom. The C(5)-C(10) bond length is 1.39 Å. The C(5)-C(6) bond length is 1.40 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(2), one C(5), and one C(7) atom. The C(6)-C(7) bond length is 1.40 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(6), one C(8), and one H(1) atom. The C(7)-C(8) bond length is 1.39 Å. The C(7)-H(1) bond length is 0.93 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(3), one C(7), and one C(9) atom. The C(8)-C(9) bond length is 1.41 Å. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one C(10), one C(4), and one C(8) atom. The C(9)-C(10) bond length is 1.39 Å. In the tenth C site, C(10) is bonded in a distorted single-bond geometry to one C(5), one C(9), and one H(2) atom. The C(10)-H(2) bond length is 0.93 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(10) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Co(1), one Co(2), and one C(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Co(1), one Co(2), and one C(2) atom. In the fourth O site, O(4) is bonded in a water-like geometry to one Co(2) and one C(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Co(1) and one C(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Co(2) and one C(3) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Co(1) and one C(4) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Co(2) and one C(4) atom. Linkers: 2 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 4 [Co]. The MOF has largest included sphere 5.51 A, density 1.25 g/cm3, surface area 2920.11 m2/g, accessible volume 0.43 cm3/g