CdCH2C2O4 crystallizes in the trigonal R-3 space group. Cd(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted corner-sharing CdO6 pentagonal pyramids. The Cd(1)-O(2) bond length is 2.30 Å. The Cd(1)-O(4) bond length is 2.32 Å. There is one shorter (2.28 Å) and one longer (2.54 Å) Cd(1)-O(1) bond length. There is one shorter (2.29 Å) and one longer (2.53 Å) Cd(1)-O(3) bond length. There are three inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.24 Å. In the second C site, C(2) is bonded in a water-like geometry to one C(3) and two equivalent H(1,2) atoms. The C(2)-C(3) bond length is 1.51 Å. Both C(2)-H(1,2) bond lengths are 0.97 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one O(3), and one O(4) atom. The C(3)-O(3) bond length is 1.26 Å. The C(3)-O(4) bond length is 1.25 Å. H(1,2) is bonded in a single-bond geometry to one C(2) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Cd(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to one Cd(1) and one C(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Cd(1) and one C(3) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Cd(1) and one C(3) atom. Linkers: 6 [O]C(=O)CC([O])=O. Metal clusters: 6 [Cd]. The MOF has largest included sphere 4.84 A, density 2.06 g/cm3, surface area 2645.46 m2/g, accessible volume 0.27 cm3/g