New Polymorphic Structures of Uranyl Butyrate and Crotonate

AbstractNew polymorphs of diaquadicrotonato‐ and diaquadibutyratodioxidouranium(VI) were synthesized. X‐ray diffraction analysis at low and room temperatures revealed the monoclinic crystal system for both compounds at both room and low temperatures. New structures contain molecular complexes in which uranium atoms are coordinated by two bidentate carboxylate ions and two water molecules. The crystal structures feature the same packing motif that constitutes layers formed by hydrogen bonds. IR spectroscopy uncovered differences in vibrations of carboxyl and uranyl groups. Voronoi‐Dirichlet parameters of the synthesized compounds and some previously published uranyl carboxylates that have similar complex and crystal structures to the new ones were compared. The new structures demonstrate once again that the volume of Voronoi‐Dirichlet polyhedron of the uranium atom in U sublattice depends on the nature of carboxylate ion alkyl chain.