Co5H4(C10O9)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(9) atom to form distorted CoO5 square pyramids that share  a cornercorner with one Co(3)O6 octahedra and corners with two equivalent Co(2)O5 square pyramids. The corner-sharing octahedral tilt angles are 62°. The Co(1)-O(1) bond length is 2.02 Å. The Co(1)-O(2) bond length is 2.07 Å. The Co(1)-O(4) bond length is 2.35 Å. The Co(1)-O(6) bond length is 2.13 Å. The Co(1)-O(9) bond length is 2.12 Å. In the second Co site, Co(2) is bonded to one O(1), one O(3), one O(4), one O(7), and one O(8) atom to form CoO5 square pyramids that share corners with two equivalent Co(1)O5 square pyramids and  an edgeedge with one Co(3)O6 octahedra. The Co(2)-O(1) bond length is 2.09 Å. The Co(2)-O(3) bond length is 2.06 Å. The Co(2)-O(4) bond length is 2.07 Å. The Co(2)-O(7) bond length is 2.13 Å. The Co(2)-O(8) bond length is 2.03 Å. In the third Co site, Co(3) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing CoO6 octahedra. Both Co(3)-O(1) bond lengths are 2.07 Å. Both Co(3)-O(5) bond lengths are 2.06 Å. Both Co(3)-O(7) bond lengths are 2.13 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(2), and one O(3) atom. The C(1)-C(5) bond length is 1.51 Å. The C(1)-O(2) bond length is 1.24 Å. The C(1)-O(3) bond length is 1.26 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(4), one C(8), and one C(9) atom. The C(2)-C(4) bond length is 1.51 Å. The C(2)-C(8) bond length is 1.39 Å. The C(2)-C(9) bond length is 1.41 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(5), one C(6), and one C(7) atom. The C(3)-C(5) bond length is 1.39 Å. The C(3)-C(6) bond length is 1.38 Å. The C(3)-C(7) bond length is 1.50 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(7), and one O(9) atom. The C(4)-O(7) bond length is 1.27 Å. The C(4)-O(9) bond length is 1.23 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(8) atom. The C(5)-C(8) bond length is 1.39 Å. In the sixth C site, C(6) is bonded in a distorted single-bond geometry to one C(3), one C(9), and one H(1) atom. The C(6)-C(9) bond length is 1.38 Å. The C(6)-H(1) bond length is 0.93 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(5), and one O(8) atom. The C(7)-O(5) bond length is 1.25 Å. The C(7)-O(8) bond length is 1.25 Å. In the eighth C site, C(8) is bonded in a distorted single-bond geometry to one C(2), one C(5), and one H(2) atom. The C(8)-H(2) bond length is 0.93 Å. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one C(10), one C(2), and one C(6) atom. The C(9)-C(10) bond length is 1.50 Å. In the tenth C site, C(10) is bonded in a distorted bent 120 degrees geometry to one C(9), one O(4), and one O(6) atom. The C(10)-O(4) bond length is 1.26 Å. The C(10)-O(6) bond length is 1.25 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(6) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(8) atom. There are nine 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 Co(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Co(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Co(2) and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Co(1), one Co(2), and one C(10) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Co(3) and one C(7) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Co(1) and one C(10) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one C(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Co(2) and one C(7) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Co(1) and one C(4) atom. Linkers: 4 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 10 [Co]. The MOF has largest included sphere 5.86 A, density 1.56 g/cm3, surface area 2501.62 m2/g, accessible volume 0.35 cm3/g