CuH6(CO2)4 crystallizes in the orthorhombic Pbca space group. Cu(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Cu(1)-O(1) bond lengths are 1.95 Å. Both Cu(1)-O(2) bond lengths are 2.00 Å. Both Cu(1)-O(3) bond lengths are 2.50 Å. There are two inequivalent C sites. In the first C site, C(2) is bonded in a trigonal planar geometry to one H(2), one O(3), and one O(4) atom. The C(2)-H(2) bond length is 1.10 Å. The C(2)-O(3) bond length is 1.23 Å. The C(2)-O(4) bond length is 1.32 Å. In the second C site, C(1) is bonded in a trigonal planar geometry to one H(1), one O(1), and one O(2) atom. The C(1)-H(1) bond length is 1.10 Å. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.28 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(2) atom. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(2) and one O(4) atom. The H(3)-O(2) bond length is 1.64 Å. The H(3)-O(4) bond length is 1.02 Å. There are four inequivalent O sites. In the first O site, O(4) is bonded in a bent 120 degrees geometry to one C(2) and one H(3) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Cu(1) and one C(2) atom. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Cu(1), one C(1), and one H(3) atom. Linkers: 8 [O]C=O. Metal clusters: 4 [Cu]. RCSR code: sql. The MOF has largest included sphere 1.92 A, density 1.98 g/cm3, surface area 4008.61 m2/g, accessible volume 0.10 cm3/g