Lithium, sodium and strontium fluoroglutaratouranylates: structure and some properties

Using X-ray diffraction analysis, the structure of the crystals of Li(UO2)2(C5H6O4)2F⋅6H2O (I), NaUO2(C5H6O4)F⋅4H2O (II) and Sr(UO2)2(C5H6O4)2F2⋅8H2O (III) was studied for the first time. The uranium-containing structural units in crystals of I are 1D complexes [UO2(C5H6O4)F0.5(H2O)]0.5– with the crystal chemical formula AQ02M20.5M1, where A = UO22+, Q02 = C5H6O42–, M2= F–, M1 = H2O, and in II and III, 1D complexes of the same composition and structure [UO2(C5H6O4)F]– with the crystal chemical formula AQ02M2. In all compounds, the U(VI) atoms implement hexagonal-bipyramidal coordination, forming coordination polyhedra UO2FO5 (I) and UO2F2O4 (II and III). It was found that the long-characterized uranyl fluoroglutarate {UJUBEG}, for which the composition [UO2(С5H6O4)F]⋅2H2O was erroneously indicated, contradicting the principle of electrical neutrality, should be considered as (Н3O)[UO2(С5H6O4)F]⋅H2O.