NdC2P2H3O7CH3NH2 crystallizes in the monoclinic P2_1/c space group. The structure consists of four methylammonium molecules inside a NdC2P2H3O7 framework. In the NdC2P2H3O7 framework, Nd(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Nd(1)-O(1) bond length is 2.32 Å. The Nd(1)-O(2) bond length is 2.32 Å. The Nd(1)-O(3) bond length is 2.41 Å. The Nd(1)-O(4) bond length is 2.69 Å. The Nd(1)-O(5) bond length is 2.54 Å. The Nd(1)-O(6) bond length is 2.43 Å. The Nd(1)-O(7) bond length is 2.32 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted tetrahedral geometry to one C(2), one P(1), one P(2), and one O(4) atom. The C(1)-C(2) bond length is 1.54 Å. The C(1)-P(1) bond length is 1.86 Å. The C(1)-P(2) bond length is 1.86 Å. The C(1)-O(4) bond length is 1.46 Å. In the second C site, C(2) is bonded in a distorted water-like geometry to one C(1), one H(5), and one H(6) atom. The C(2)-H(5) bond length is 1.10 Å. The C(2)-H(6) bond length is 1.10 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 corner-sharing PCO3 tetrahedra. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.54 Å. In the second P site, P(2) is bonded to one C(1), one O(5), one O(6), and one O(7) atom to form corner-sharing PCO3 tetrahedra. The P(2)-O(5) bond length is 1.56 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.53 Å. There are three inequivalent H sites. In the first H site, H(6) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(1) is bonded in a distorted single-bond geometry to one O(4) and one O(5) atom. The H(1)-O(4) bond length is 1.01 Å. The H(1)-O(5) bond length is 1.68 Å. In the third H site, H(5) is bonded in a single-bond geometry to one C(2) atom. There are seven inequivalent O sites. In the first O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Nd(1) and one P(1) atom. In the second O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Nd(1) and one P(1) atom. In the third O site, O(4) is bonded in a distorted water-like geometry to one Nd(1), one C(1), and one H(1) atom. In the fourth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Nd(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Nd(1), one P(2), and one H(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Nd(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Nd(1) and one P(2) atom. Linkers: 4 [NH3]CCC(P(=O)([O])[O])(P(=O)([O])[O])O. Metal clusters: 4 [Nd]. The MOF has largest included sphere 1.85 A, density 2.95 g/cm3, surface area 2095.01 m2/g, accessible volume 0.06 cm3/g