CdC4NH2O5 crystallizes in the triclinic P-1 space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in an octahedral geometry to two equivalent N(1), two equivalent O(1), and two equivalent O(3) atoms. Both Cd(1)-N(1) bond lengths are 2.41 Å. Both Cd(1)-O(1) bond lengths are 2.43 Å. Both Cd(1)-O(3) bond lengths are 2.24 Å. In the second Cd site, Cd(2) is bonded in an octahedral geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. Both Cd(2)-O(2) bond lengths are 2.41 Å. Both Cd(2)-O(4) bond lengths are 2.25 Å. Both Cd(2)-O(5) bond lengths are 2.31 Å. There are four 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(3), and one O(4) atom. The C(1)-C(2) bond length is 1.52 Å. The C(1)-O(3) bond length is 1.26 Å. The C(1)-O(4) bond length is 1.26 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 N(1) atom. The C(2)-C(3) bond length is 1.41 Å. The C(2)-N(1) bond length is 1.34 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one C(4), and one N(1) atom. The C(3)-C(4) bond length is 1.52 Å. The C(3)-N(1) bond length is 1.34 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(1), and one O(2) atom. The C(4)-O(1) bond length is 1.27 Å. The C(4)-O(2) bond length is 1.27 Å. N(1) is bonded in a distorted trigonal planar geometry to one Cd(1), one C(2), and one C(3) atom. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. The H(1)-O(5) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. The H(2)-O(5) bond length is 0.99 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cd(1) and one C(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Cd(2) and one C(4) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Cd(1) and one C(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cd(2) and one C(1) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Cd(2), one H(1), and one H(2) atom. Linkers: 2 [O]C(=O)c1[c]nc(C([O])=O)c(C([O])=O)n1 ,1 [O]C(=O)c1nc(C([O])=O)c(C([O])=O)nc1C([O])=O. Metal clusters: 2 [Cd]. The MOF has largest included sphere 1.82 A, density 3.06 g/cm3, surface area 2078.09 m2/g, accessible volume 0.02 cm3/g