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Title: Ionothermal synthesis of uranyl compounds that incorporate imidazole derivatives

Ionothermal reactions of uranyl nitrate with various salts in methylimidazolium-based ionic liquids have produced single crystals of three uranyl compounds that incorporate imidazole derivatives as charge-balancing cations. (C{sub 4}H{sub 7}N{sub 2})[(UO{sub 2})(PO{sub 3}F)(F)] (1) crystallizes in space group C2, a=17.952(1) A, b=6.9646(6) A, c=8.5062(7) A, {beta}=112.301(1) Degree-Sign , (C{sub 6}H{sub 11}N{sub 2}){sub 2}[(UO{sub 2})(SO{sub 4}){sub 2}] (2) crystallizes in space group C2/c, a=31.90(1) A, b=9.383(5) A, c=13.770(7) A, {beta}=93.999(7) Degree-Sign and (C{sub 6}H{sub 11}N{sub 2})[(UO{sub 2}){sub 2}(PO{sub 4})(HPO{sub 4}) (3) crystallizes in space group P2{sub 1}/n, a=9.307(2), b=18.067(4), c=9.765(2), {beta}=93.171(2). The U{sup 6+} cations are present as (UO{sub 2}){sup 2+} uranyl ions coordinated by three O atoms and two F atoms in 1 and five O atoms in 2 and 3 to give pentagonal bipyramids. The structural unit in 1 is composed of F-sharing dimers of uranyl pentagonal bipyramids linked into sheets through corner-sharing fluorophosphate tetrahedra. The structural unit in 2 is composed of uranyl pentagonal bipyramids with one chelating sulfate tetrahedron linked into chains by three other corner-sharing sulfate tetrahedra. In 3, the structural unit is composed of chains of uranyl pentagonal bipyramids linked into sheets through edge- and corner-sharing phosphate and hydrogen phosphate tetrahedra. N-methylimidazolium cations occupy themore » interstitial space between the uranyl fluorophosphate sheets in 1, whereas 1-ethyl-3-methylimidazolium cations link the uranyl sulfate and phosphate units in 2 and 3 into extended structures. - Graphical abstract: The synthesis of uranyl compounds by ionothermal treatment is explored, and provides three novel compounds and insights concerning the role of water in controlling the structural units. Highlights: Black-Right-Pointing-Pointer Ionothermal syntheses have produced three new uranyl compounds. Black-Right-Pointing-Pointer Imidazole derivatives are incorporated as charge-balancing agents. Black-Right-Pointing-Pointer X-ray and spectroscopic analyses reveal variability between imidazole derivatives. Black-Right-Pointing-Pointer This method offers synthetic insight in the absence of water at low temperatures.« less
Authors:
; ;  [1] ;  [1] ;  [2]
  1. Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22131186
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 197; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CATIONS; CHELATING AGENTS; HYDROGEN PHOSPHATES; MOLTEN SALTS; MONOCLINIC LATTICES; MONOCRYSTALS; SPACE GROUPS; SYNTHESIS; URANIUM DIOXIDE; URANIUM IONS; URANYL NITRATES; URANYL SULFATES; X-RAY DIFFRACTION