Cd3(CO2)8 crystallizes in the cubic I-43d space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to four equivalent O(1) and four equivalent O(2) atoms to form distorted edge-sharing CdO8 hexagonal bipyramids. All Cd(1)-O(1) bond lengths are 2.40 Å. All Cd(1)-O(2) bond lengths are 2.37 Å. In the second Cd site, Cd(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted edge-sharing CdO6 pentagonal pyramids. Both Cd(2)-O(1) bond lengths are 2.26 Å. Both Cd(2)-O(3) bond lengths are 2.24 Å. Both Cd(2)-O(4) bond lengths are 2.28 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(1) and one O(4) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(4) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(3) atom. The C(2)-O(2) bond length is 1.25 Å. The C(2)-O(3) bond length is 1.26 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cd(1), one Cd(2), and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Cd(1) and one C(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Cd(2) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Cd(2) and one C(1) atom. Linkers: 24 [O]C(=O)C([O])=O. Metal clusters: 18 [Cd]. The MOF has largest included sphere 4.48 A, density 2.16 g/cm3, surface area 2513.18 m2/g, accessible volume 0.17 cm3/g