Cu(C5H4NPO3) crystallizes in the triclinic P-1 space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one N(1), one O(4), one O(5), and two equivalent O(1) atoms to form distorted CuNO4 square pyramids that share corners with two equivalent P(1)CO3 tetrahedra, corners with two equivalent P(2)CO3 tetrahedra, and  an edgeedge with one Cu(1)NO4 square pyramid. The Cu(1)-N(1) bond length is 1.97 Å. The Cu(1)-O(4) bond length is 1.99 Å. The Cu(1)-O(5) bond length is 1.99 Å. There is one shorter (1.95 Å) and one longer (2.42 Å) Cu(1)-O(1) bond length. In the second Cu site, Cu(2) is bonded in a distorted rectangular see-saw-like geometry to one N(2), one O(2), one O(3), and one O(6) atom. The Cu(2)-N(2) bond length is 2.00 Å. The Cu(2)-O(2) bond length is 1.95 Å. The Cu(2)-O(3) bond length is 1.95 Å. The Cu(2)-O(6) bond length is 2.01 Å. There are ten inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(5), and one P(1) atom. The C(1)-C(2) bond length is 1.40 Å. The C(1)-C(5) bond length is 1.40 Å. The C(1)-P(1) bond length is 1.82 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(3), and one H(1) atom. The C(2)-C(3) bond length is 1.39 Å. The C(2)-H(1) bond length is 1.09 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(2) atom. The C(3)-N(1) bond length is 1.35 Å. The C(3)-H(2) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(5), one N(1), and one H(3) atom. The C(4)-C(5) bond length is 1.39 Å. The C(4)-N(1) bond length is 1.35 Å. The C(4)-H(3) bond length is 1.09 Å. In the fifth C site, C(5) is bonded in a distorted single-bond geometry to one C(1), one C(4), and one H(4) atom. The C(5)-H(4) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(10), one C(7), and one P(2) atom. The C(6)-C(10) bond length is 1.40 Å. The C(6)-C(7) bond length is 1.40 Å. The C(6)-P(2) bond length is 1.83 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(5) atom. The C(7)-C(8) bond length is 1.39 Å. The C(7)-H(5) bond length is 1.09 Å. In the eighth C site, C(8) is bonded in a distorted trigonal planar geometry to one C(7), one N(2), and one H(6) atom. The C(8)-N(2) bond length is 1.35 Å. The C(8)-H(6) bond length is 1.09 Å. In the ninth C site, C(9) is bonded in a distorted trigonal planar geometry to one C(10), one N(2), and one H(7) atom. The C(9)-C(10) bond length is 1.39 Å. The C(9)-N(2) bond length is 1.35 Å. The C(9)-H(7) bond length is 1.09 Å. In the tenth C site, C(10) is bonded in a distorted trigonal planar geometry to one C(6), one C(9), and one H(8) atom. The C(10)-H(8) bond length is 1.09 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one C(1), one O(1), one O(2), and one O(3) atom to form distorted PCO3 tetrahedra that share corners with two equivalent Cu(1)NO4 square pyramids. 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. In the second P site, P(2) is bonded to one C(6), one O(4), one O(5), and one O(6) atom to form distorted PCO3 tetrahedra that share corners with two equivalent Cu(1)NO4 square pyramids. The P(2)-O(4) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.55 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Cu(1), one C(3), and one C(4) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Cu(2), one C(8), and one C(9) atom. There are eight 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(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(4) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(5) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(7) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(8) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(9) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(10) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Cu(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Cu(2) and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Cu(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Cu(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Cu(2) and one P(2) atom. Linkers: 4 [O]P([O])(=O)c1ccncc1. Metal clusters: 4 [Cu]. The MOF has largest included sphere 3.68 A, density 1.96 g/cm3, surface area 2882.86 m2/g, accessible volume 0.15 cm3/g