CoC2PH2O7 crystallizes in the monoclinic P2_1/c space group. Co(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CoO6 octahedra that share corners with two equivalent P(1)HO3 tetrahedra. The Co(1)-O(2) bond length is 2.08 Å. The Co(1)-O(3) bond length is 2.04 Å. The Co(1)-O(4) bond length is 2.12 Å. The Co(1)-O(5) bond length is 2.11 Å. The Co(1)-O(6) bond length is 2.11 Å. The Co(1)-O(7) bond length is 2.09 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(4) and one O(5) atom. The C(1)-O(4) bond length is 1.25 Å. The C(1)-O(5) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(6) and one O(7) atom. The C(2)-O(6) bond length is 1.26 Å. The C(2)-O(7) bond length is 1.25 Å. P(1) is bonded to one H(1), one O(1), one O(2), and one O(3) atom to form distorted PHO3 tetrahedra that share corners with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. The P(1)-H(1) bond length is 1.29 Å. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.51 Å. The P(1)-O(3) bond length is 1.49 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one P(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(1) atom. The H(2)-O(1) bond length is 0.82 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one P(1) and one H(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Co(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Co(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Co(1) and one C(1) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Co(1) and one C(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Co(1) and one C(2) atom. Linkers: 4 [O]C(=O)C([O])=O. Metal clusters: 4 [Co]. The MOF has largest included sphere 4.39 A, density 1.55 g/cm3, surface area 3263.65 m2/g, accessible volume 0.34 cm3/g