U(CO2)5 crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Both U(1)-O(1) bond lengths are 2.46 Å. Both U(1)-O(2) bond lengths are 2.51 Å. Both U(1)-O(3) bond lengths are 2.45 Å. Both U(1)-O(4) bond lengths are 2.45 Å. Both U(1)-O(5) bond lengths are 2.44 Å. There are five inequivalent C sites. In the first C site, C(3) is bonded in a distorted bent 120 degrees geometry to two equivalent O(3) atoms. Both C(3)-O(3) bond lengths are 1.26 Å. In the second C site, C(4) is bonded in a distorted bent 120 degrees geometry to two equivalent O(2) atoms. Both C(4)-O(2) bond lengths are 1.26 Å. In the third C site, C(1) is bonded in a distorted bent 120 degrees geometry to two equivalent O(1) atoms. Both C(1)-O(1) bond lengths are 1.26 Å. In the fourth C site, C(2) is bonded in a distorted bent 120 degrees geometry to two equivalent O(5) atoms. Both C(2)-O(5) bond lengths are 1.24 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to two equivalent O(4) atoms. Both C(5)-O(4) bond lengths are 1.30 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one U(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one U(1) and one C(4) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one U(1) and one C(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one U(1) and one C(5) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one U(1) and one C(2) atom. Linkers: 29 [O]C(=O)C([O])=O. Metal clusters: 12 [U]. The MOF has largest included sphere 7.39 A, density 2.25 g/cm3, surface area 1843.99 m2/g, accessible volume 0.22 cm3/g