The Structure of Dinuclear Fluorooxalatouranylates Rb5[(UO2)2(C2O4)4F] • 2H2O and Ba5[(UO2)2(C2O4)4F]2 • 22H2O

Using X-ray diffraction analysis, the structure of the first obtained crystals of Rb5[(UO2)2(C2O4)4F] • 2H2O (I) and Ba5[(UO2)2(C2O4)4F]2 • 22H2O (II) was studied (CCDC № 2392480 (I), 2392481 (II)). The urani-um-containing structural units are dinuclear complexes of the same composition [(UO2)2(C2O4)4F]5-, but different structure, which is described by the crystallochemical formulas: A2T11B013M1 (I) and A2B014M2 (II), where A = UO22+, T11 or B01 = C2O42-, and M1 or M2 = F-. The complexes contain crystallographically nonequivalent U(VI) atoms, which are part of uranyl ions and implement pentagonal-bipyramidal coordination. In I, the U(VI) atoms form coordination polyhedra UO2FO4 and UO2O5, and in II - only UO2FO4. In both structures, the dinuclear complexes [(UO2)2(C2O4)4F]5- are connected to form a 3D framework due to the coordination bonds R-O and R-F (R = Rb or Ba), in the voids of which water molecules are located, participating in the formation of a set of hydrogen bonds. The obtained IR spectroscopy results for I and II are consistent with the X-ray diffraction data.