CdC4 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a rectangular see-saw-like geometry to two equivalent C(2) and two equivalent C(3) atoms. Both Cd(1)-C(2) bond lengths are 2.35 Å. Both Cd(1)-C(3) bond lengths are 2.24 Å. In the second Cd site, Cd(2) is bonded in a tetrahedral geometry to four equivalent C(1) atoms. All Cd(2)-C(1) bond lengths are 2.21 Å. There are three inequivalent C sites. In the first C site, C(1) is bonded in a distorted single-bond geometry to one Cd(2) and one C(2) atom. The C(1)-C(2) bond length is 1.14 Å. In the second C site, C(2) is bonded in a linear geometry to one Cd(1) and one C(1) atom. In the third C site, C(3) is bonded in a linear geometry to one Cd(1) and one C(3) atom. The C(3)-C(3) bond length is 1.19 Å. Linkers: 1 [C]#[C]. Metal clusters: . The MOF has largest included sphere 5.15 A, density 1.13 g/cm3, surface area 3241.04 m2/g, accessible volume 0.56 cm3/g