Cu(HCOO)2 crystallizes in the orthorhombic P2_12_12_1 space group. Cu(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Cu(1)-O(1) bond length is 2.26 Å. The Cu(1)-O(2) bond length is 1.95 Å. The Cu(1)-O(3) bond length is 2.01 Å. The Cu(1)-O(4) bond length is 1.99 Å. There are two inequivalent C sites. In the first 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 0.95 Å. The C(1)-O(1) bond length is 1.25 Å. The C(1)-O(2) bond length is 1.26 Å. In the second 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 0.95 Å. The C(2)-O(3) bond length is 1.27 Å. The C(2)-O(4) bond length is 1.26 Å. There are two 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. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one C(1) atom. In the second O site, O(2) 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 bent 120 degrees geometry to one Cu(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Cu(1) and one C(2) atom. Linkers: 8 [O]C=O. Metal clusters: 4 [Cu]. RCSR code: dia. The MOF has largest included sphere 5.33 A, density 1.10 g/cm3, surface area 3761.91 m2/g, accessible volume 0.58 cm3/g