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A cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) was developed in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. The method was applied to determine REE abundances in four uraninite (ideally UO2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondary uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K+ and Pb2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.

Three new multidimensional bimetallic UO22+-3d three-dimensional complexes were crystallized in high yield under mild hydrothermal conditions: [Mn(H2O)]2[(UO2)4(PO3C6H4PO3)3(bipym)]·2H2O (1), [Ni(H2O)]2[(UO2)3(O3PC6H4PO3)(O3PC6H4PO3H)2(bipym)]·6H2O (2), and Zn[(UO2)(HO3PC6H4PO3)(HO3PC6H4PO3H)0.5(bipym)0.5] (3), where bipym = 2,2-bipyrimidine. The structure of 1 is composed of edge-sharing dimers of uranyl pentagonal bipyramids that are linked by rigid phenyl spacers to form pillared three-dimensional networks. This compound is remarkable in that the [Mn2(H2O)2(bipym)]4+ moiety is incorporated within the uranyl phosphonate frameworks without reducing the dimensionality of the overall structure. Compound 2 consists of uranyl tetragonal and pentagonal bipyramids that are linked by phosphonate groups to form a pillared three-dimensional framework with channels that are occupied by the [Ni2(H2O)2(bipym)2]4+ moiety. In compound 3, edge-sharing dimers of uranyl pentagonal bipyramids are connected through the pho...

Three new multidimensional polymetallic uranyl diphosphonates were crystallized under mild hydrothermal conditions: [Cu(H2O)]2{(UO2)4F2[(PO3C6H4)(C6H4PO3H)3]2(bipym)}·6H2O (1), [Cu(H2O)]2{(UO2)4[(C6H4PO3)(C6H4PO3H)]4(bipym)} (2), and Cu{(UO2)(C6H4PO3)2(bipym)}·H2O (3). Compound 1 consists of UO6F pentagonal bipyramids connected by diphosphonate moieties into a tubular channel. The Cu(2+) cations are stabilized between the nanotubular subunits by 2,2'-bipyrimidine (bipym). The structure of 2 is similar to 1, except that it consists of relatively rare UO6 tetragonal bipyramids bridged by diphosphonate groups. Compound 3 also contains UO6 tetragonal bipyramids. Unlike compounds 1 and 2, only two of the tetradentate N atoms of the binucleating bipym group are coordinated. All three compounds show luminescent properties under ambient conditions, with evidence of the characteristic vibronically coupled charge-transfer based uranyl cation emissions.