Na2MoC4NH9O9 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form edge-sharing NaO6 octahedra. Both Na(1)-O(1) bond lengths are 2.34 Å. Both Na(1)-O(2) bond lengths are 2.36 Å. Both Na(1)-O(5) bond lengths are 2.42 Å. In the second Na site, Na(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form edge-sharing NaO6 octahedra. Both Na(2)-O(2) bond lengths are 2.44 Å. Both Na(2)-O(4) bond lengths are 2.36 Å. Both Na(2)-O(5) bond lengths are 2.37 Å. Mo(1) is bonded in a 6-coordinate geometry to one N(1), one O(1), two equivalent O(2), and two equivalent O(3) atoms. The Mo(1)-N(1) bond length is 2.34 Å. The Mo(1)-O(1) bond length is 1.76 Å. Both Mo(1)-O(2) bond lengths are 1.75 Å. Both Mo(1)-O(3) bond lengths are 2.25 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(3) and one O(4) atom. The C(1)-O(3) bond length is 1.29 Å. The C(1)-O(4) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted trigonal non-coplanar geometry to one N(1), one H(1), and one H(2) atom. The C(2)-N(1) bond length is 1.47 Å. The C(2)-H(1) bond length is 1.10 Å. The C(2)-H(2) bond length is 1.10 Å. N(1) is bonded in a 3-coordinate geometry to one Mo(1), two equivalent C(2), and one H(3) atom. The N(1)-H(3) bond length is 1.03 Å. There are five 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(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one N(1) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(4) and one O(5) atom. The H(4)-O(4) bond length is 1.71 Å. The H(4)-O(5) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. The H(5)-O(5) bond length is 0.98 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Mo(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mo(1) and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(2), one C(1), and one H(4) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Na(2), one H(4), and one H(5) atom. Linkers: 2 [O]C(=O)CNCC([O])=O ,4 O. Metal clusters: 4 [Na] ,2 [Mo]. The MOF has largest included sphere 2.95 A, density 2.21 g/cm3, surface area 2248.88 m2/g, accessible volume 0.05 cm3/g