UC3H2O4 crystallizes in the hexagonal P6_122 space group. U(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. Both U(1)-O(1) bond lengths are 2.39 Å. Both U(1)-O(2) bond lengths are 2.43 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one O(1), and one O(2) atom. The C(1)-C(2) bond length is 1.51 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 bent 120 degrees geometry to two equivalent C(1) and two equivalent H(1) atoms. Both C(2)-H(1) bond lengths are 0.95 Å. H(1) is bonded in a single-bond geometry to one C(2) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one U(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one U(1) and one C(1) atom. Linkers: 6 [O]C(=O)CC([O])=O. Metal clusters: 6 [U]. The MOF has largest included sphere 4.88 A, density 2.41 g/cm3, surface area 1885.27 m2/g, accessible volume 0.21 cm3/g