U3(C33O8)2 crystallizes in the cubic Fm-3m space group. U(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. All U(1)-O(1) bond lengths are 2.32 Å. All U(1)-O(2) bond lengths are 2.33 Å. There are five inequivalent C sites. In the first C site, C(4) is bonded in a 5-coordinate geometry to one C(3) and four equivalent C(1) atoms. The C(4)-C(3) bond length is 1.52 Å. All C(4)-C(1) bond lengths are 1.39 Å. In the second C site, C(1) is bonded in a 3-coordinate geometry to one C(1), one C(2), and one C(4) atom. The C(1)-C(1) bond length is 0.92 Å. The C(1)-C(2) bond length is 1.38 Å. In the third C site, C(2) is bonded in a 3-coordinate geometry to one C(1), one C(2), and one C(5) atom. The C(2)-C(2) bond length is 0.83 Å. The C(2)-C(5) bond length is 1.40 Å. In the fourth C site, C(5) is bonded in a 5-coordinate geometry to one C(5) and four equivalent C(2) atoms. The C(5)-C(5) bond length is 1.52 Å. In the fifth C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4) and two equivalent O(1) atoms. Both C(3)-O(1) bond lengths are 1.27 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded in a trigonal non-coplanar geometry to three equivalent U(1) atoms. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to one U(1) and one C(3) atom. Linkers: 1 [C]1[C][C][C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1[C].[O][C]=O.[O][C]=O ,6 [C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,3 [C][C]1[C][C]([C][C]2[C][C][C]2)[C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,1 [C]1[C][C][C]1.[C][C]1[C][C]([C])[C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,1 [C]1[C][C][C]1.[C][C]1[C][C][C]1[C].[C][C]1[C][C][C]1[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,2 [C][C]1[C][C][C]1.[C][C]1[C][C][C]1.[C][C]1[C][C][C]1[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,2 [C][C]1[C][C][C]1[C][C]1[C][C][C]1.[C][C]1[C][C][C]1[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,1 [C][C]1[C][C]([C][C]2[C][C][C]2)[C]1.[C][C]1[C][C][C]1[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,2 [C]1[C][C][C]1.[C]1[C][C][C]1.[C][C]1[C][C]([C])[C]1.[C][C]1[C][C][C]1[C].[O][C]=O.[O][C]=O ,2 [C]1[C]2[C][C]1[C][C]1[C][C][C]1[C]2.[C]1[C][C][C]1.[C][C]1[C][C]([C])[C]1.[O][C]=O.[O][C]=O ,1 [C][C]1[C][C]([C][C]2[C][C][C]2)[C]1.[C][C]1[C][C]([C][C]2[C][C][C]2)[C]1.[O][C]=O.[O][C]=O ,1 [C]1[C]2[C][C]1[C][C]1[C][C]([C]1)[C]2.[C][C]1[C][C][C]1[C][C]1[C][C][C]1.[O][C]=O.[O][C]=O ,1 [C]1[C]2[C][C]1[C][C]1[C][C]([C]1)[C]2.[C]1[C]2[C][C]1[C][C]1[C][C]([C]1)[C]2.[O][C]=O.[O][C]=O. Metal clusters: 1 [O].[O][U]123O[C]O[U]45([O])([O])O[C]O[U]678(O[C]O1)O[C]O[U]19(O[C]O2)(O[C]O[U]2(O[C]O3)(O[C]O4)(O[C]O[U](O[C]O5)(O[C]O6)(O[C]O1)(O7)O2)O9)O8 ,1 [O].[O].[O][U]123([O])O[C]O[U]456O[C]O[U]789O[C]O[U]%10(O[C]O4)(O[C]O1)(O[C]O[U]1(O[C]O7)(O[C]O2)(O[C]O[U](O[C]O5)(O[C]O8)(O[C]O3)(O9)O1)O%10)O6 ,1 [O].[O][U]1234O[C]O[U]567O[C]O[U]89([O])(O[C]O1)O[C]O[U]1%10([O])(O[C]O2)O[C]O[U](O[C]O5)(O[C]O3)(O[C]O[U](O[C]O6)(O[C]O8)(O[C]O1)(O9)O%10)(O7)O4 ,1 [O].[O].[O][U]123([O])O[C]O[U]4567O[C]O[U]89O[C]O[U]%10(O[C]O1)(O[C]O4)(O[C]O[U]1(O[C]O8)(O[C]O2)(O[C]O[U](O[C]O9)(O[C]O3)(O[C]O5)(O6)O1)O%10)O7. RCSR code: fcu. The MOF has largest included sphere 13.99 A, density 1.13 g/cm3, surface area 2298.65 m2/g, accessible volume 0.59 cm3/g