Nd(CO2)3C3NH6 crystallizes in the orthorhombic P2_12_12_1 space group. The structure consists of four trimethylamine molecules inside a Nd(CO2)3 framework. In the Nd(CO2)3 framework, Nd(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and two equivalent O(3) atoms. The Nd(1)-O(1) bond length is 2.35 Å. The Nd(1)-O(2) bond length is 2.40 Å. The Nd(1)-O(4) bond length is 2.47 Å. The Nd(1)-O(5) bond length is 2.49 Å. The Nd(1)-O(6) bond length is 2.43 Å. There is one shorter (2.50 Å) and one longer (2.57 Å) Nd(1)-O(3) bond length. There are three inequivalent C sites. In the first C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(2)-O(1) bond length is 1.27 Å. The C(2)-O(2) bond length is 1.26 Å. In the second C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(4)-O(3) bond length is 1.28 Å. The C(4)-O(4) bond length is 1.26 Å. In the third C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(6)-O(5) bond length is 1.27 Å. The C(6)-O(6) bond length is 1.27 Å. There are six inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Nd(1) and one C(4) atom. In the second O site, O(4) is bonded in a distorted single-bond geometry to one Nd(1) and one C(4) atom. In the third O site, O(5) is bonded in a distorted single-bond geometry to one Nd(1) and one C(6) atom. In the fourth O site, O(6) is bonded in a distorted single-bond geometry to one Nd(1) and one C(6) atom. In the fifth O site, O(1) is bonded in a bent 120 degrees geometry to one Nd(1) and one C(2) atom. In the sixth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Nd(1) and one C(2) atom. Linkers: 4 [O]C(=O)CN(CC([O])=O)CC([O])=O. Metal clusters: 4 [Nd]. The MOF has largest included sphere 2.23 A, density 2.71 g/cm3, surface area 2207.46 m2/g, accessible volume 0.07 cm3/g