CoC4PH5(NO2)2 crystallizes in the monoclinic Cc space group. Co(1) is bonded to one N(1), one N(2), one O(1), one O(2), one O(3), and one O(4) atom to form CoN2O4 octahedra that share corners with three equivalent P(1)CO3 tetrahedra. The Co(1)-N(1) bond length is 2.08 Å. The Co(1)-N(2) bond length is 2.10 Å. The Co(1)-O(1) bond length is 2.07 Å. The Co(1)-O(2) bond length is 2.09 Å. The Co(1)-O(3) bond length is 2.06 Å. The Co(1)-O(4) bond length is 2.25 Å. There are four inequivalent C sites. In the first C site, C(3) is bonded in a distorted bent 120 degrees geometry to one N(2) and one H(4) atom. The C(3)-N(2) bond length is 1.35 Å. The C(3)-H(4) bond length is 1.08 Å. In the second C site, C(4) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(5) atom. The C(4)-N(1) bond length is 1.34 Å. The C(4)-H(5) bond length is 1.09 Å. In the third C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one P(1), and one N(1) atom. The C(1)-C(2) bond length is 1.40 Å. The C(1)-P(1) bond length is 1.83 Å. The C(1)-N(1) bond length is 1.35 Å. In the fourth C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one N(2), and one H(3) atom. The C(2)-N(2) bond length is 1.35 Å. The C(2)-H(3) bond length is 1.09 Å. P(1) is bonded to one C(1), one O(1), one O(2), and one O(3) atom to form PCO3 tetrahedra that share corners with three equivalent Co(1)N2O4 octahedra. The corner-sharing octahedral tilt angles range from 42-61°. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.54 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Co(1), one C(1), and one C(4) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Co(1), one C(2), and one C(3) atom. There are five inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) and one O(4) atom. The H(1)-O(3) bond length is 1.65 Å. The H(1)-O(4) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. The H(2)-O(4) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one C(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(3) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Co(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(1), one P(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Co(1), one H(1), and one H(2) atom. Linkers: 1 [O]P([O])c1cnccn1 ,2 [O]P([O])(=O)c1cnccn1 ,1 [O]P([O])(=O)c1cn[c][c]n1. Metal clusters: 2 [Co]. The MOF has largest included sphere 2.20 A, density 2.34 g/cm3, surface area 2425.52 m2/g, accessible volume 0.07 cm3/g