CoC4H4O5 crystallizes in the orthorhombic P2_12_12_1 space group. Co(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form corner-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles are 60°. The Co(1)-O(1) bond length is 2.07 Å. The Co(1)-O(2) bond length is 2.06 Å. The Co(1)-O(4) bond length is 2.11 Å. The Co(1)-O(5) bond length is 2.14 Å. There is one shorter (2.05 Å) and one longer (2.18 Å) Co(1)-O(3) bond length. There are four inequivalent C sites. In the first C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(4)-O(3) bond length is 1.30 Å. The C(4)-O(4) bond length is 1.25 Å. In the second C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.27 Å. In the third C site, C(2) is bonded in a distorted trigonal non-coplanar geometry to one H(1), one H(2), and one O(5) atom. The C(2)-H(1) bond length is 1.10 Å. The C(2)-H(2) bond length is 1.10 Å. The C(2)-O(5) bond length is 1.43 Å. In the fourth C site, C(3) is bonded in a distorted trigonal non-coplanar geometry to one H(3), one H(4), and one O(5) atom. The C(3)-H(3) bond length is 1.10 Å. The C(3)-H(4) bond length is 1.09 Å. The C(3)-O(5) bond length is 1.43 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(3) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(3) atom. There are five 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 distorted bent 120 degrees geometry to one Co(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Co(1) and one C(4) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Co(1) and one C(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Co(1), one C(2), and one C(3) atom. Linkers: 4 [O]C(=O)COCC([O])=O. Metal clusters: 4 [Co]. The MOF has largest included sphere 1.71 A, density 2.41 g/cm3, surface area 2450.15 m2/g, accessible volume 0.04 cm3/g