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Competitive Coordination of the Uranyl Ion by Perchlorate and Water ‐ The Crystal Structures of UO 2 (ClO 4 ) 2 ·3H 2 O and UO 2 (ClO 4 ) 2 ·5H 2 O and a Redetermination of UO 2 (ClO 4 ) 2 ·7H 2 O
Author(s) -
Fischer Andreas
Publication year - 2003
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.200200450
Subject(s) - uranyl , monoclinic crystal system , orthorhombic crystal system , perchlorate , chemistry , crystallography , perchloric acid , molecule , crystal structure , hydrate , ion , denticity , stoichiometry , coordination number , inorganic chemistry , crystallization , organic chemistry
By slow evaporation of solutions containing UO 2 (ClO 4 ) 2 and an excess of HClO 4 , single crystals of [UO 2 (ClO 4 ) 2 (H 2 O) 3 ] ( 1 ) and [UO 2 (H 2 O) 5 ](ClO 4 ) 2 ( 2 ) were obtained and their structures were determined. From similar solutions prepared from stoichiometric amounts of UO 3 and perchloric acid, crystals of [UO 2 (H 2 O) 5 ](ClO 4 ) 2 ·2H 2 O ( 3 ) were obtained. The trihydrate (monoclinic, P 2 1 / c , a = 545.44(1) pm, b = 1811.09(5) pm, c = 1032.46(2) pm, β = 90.016(1)°) consists of uranyl ions, which are coordinated by two monodentate perchlorate ions and three water molecules. The pentahydrate (monoclinic, P 2 1 / n , a = 529.35(2) pm, b = 1645.43(6) pm, c = 1480.18(6) pm, β = 99.847(1)°) contains uranyl ions coordinated by five water molecules. The same structural unit can be found in the heptahydrate, whose structure was re‐determined (orthorhombic, Pbcn , a = 920.9(3) pm, b = 1067.9(3) pm, c = 1445.7(3) pm). In this structure, two molecules of water of crystallization are present.