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Polymorphism in Alkali Metal Uranyl Nitrates: Synthesis and Crystal Structure of γ‐K(UO 2 )(NO 3 ) 3
Author(s) -
Jouffret Laurent J.,
Krivovichev Sergey V.,
Burns Peter C.
Publication year - 2011
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201100200
Subject(s) - uranyl , orthorhombic crystal system , alkali metal , crystallography , polymorphism (computer science) , chemistry , crystal structure , aqueous solution , metal , evaporation , ion , inorganic chemistry , organic chemistry , biochemistry , genotype , gene , physics , thermodynamics
Single crystals of γ‐K(UO 2 )(NO 3 ) 3 were prepared from aqueous solutions by evaporation. The crystal structure [orthorhombic, Pbca (61), a = 9.2559(3) Å, b = 12.1753(3) Å, c = 15.8076(5) Å, V = 1781.41(9) Å 3 , Z = 8] was determined by direct methods and refined to R 1 = 0.0267 on the basis of 3657 unique observed reflections. The structure is composed of isolated anionic uranyl trinitrate units, [(UO 2 )(NO 3 ) 3 ] – , that are linked through eleven‐coordinated K + cations. Both known polymorphs of K(UO 2 )(NO 3 ) 3 (α‐ and γ‐phases) can be considered as based upon sheets of isolated complex [(UO 2 )(NO 3 ) 3 ] – ions separated by K + cations. The existence of polymorphism in the two K[UO 2 (NO 3 ) 3 ] polymorphs is due to the different packing modes of uranyl trinitrate clusters that adopt the same two‐dimensional but different three‐dimensional arrangements.