CdC6NH3O3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent N(1), two equivalent O(1), and two equivalent O(3) atoms to form edge-sharing CdN2O4 octahedra. Both Cd(1)-N(1) bond lengths are 2.34 Å. Both Cd(1)-O(1) bond lengths are 2.41 Å. Both Cd(1)-O(3) bond lengths are 2.29 Å. In the second Cd site, Cd(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form edge-sharing CdO6 octahedra. Both Cd(2)-O(1) bond lengths are 2.40 Å. Both Cd(2)-O(2) bond lengths are 2.31 Å. Both Cd(2)-O(3) bond lengths are 2.23 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.26 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(6) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(6) bond length is 1.40 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2) and one H(1) atom. The C(3)-H(1) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a distorted single-bond geometry to one O(3) atom. The C(4)-O(3) bond length is 1.33 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(2) atom. The C(5)-N(1) bond length is 1.34 Å. The C(5)-H(2) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(3) atom. The C(6)-N(1) bond length is 1.35 Å. The C(6)-H(3) bond length is 1.09 Å. N(1) is bonded in a trigonal planar geometry to one Cd(1), one C(5), and one C(6) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(5) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(6) atom. There are three inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Cd(1), one Cd(2), and one C(4) atom. In the second O site, O(1) is bonded in a distorted single-bond geometry to one Cd(1), one Cd(2), and one C(1) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Cd(2) and one C(1) atom. Linkers: 4 [O]C(=O)c1cncc([O])c1. Metal clusters: 4 [Cd]. The MOF has largest included sphere 1.86 A, density 2.65 g/cm3, surface area 2664.19 m2/g, accessible volume 0.08 cm3/g