The crystal structure of meta-uranocircite II, Ba(UO 2 ) 2 (PO 4 ) 2 ·6H 2 O

摘要: The crystal structure of meta-uranocircite II, Ba(UO2)2(PO4)2·6H2O, has been determined with a synthetic using three-dimensional X-ray techniques.R=0.071 andR w =0.064 were obtained for 1743 observed reflections. Ba(UO2)2(PO4)2·6H2O is monoclinic, space groupP1121/a, a=9.789,b=9.822,c=16.868 A, γ=89.95° andZ=4. consists slightly corrugated UO2PO4 layers parallel (001). are connected by Ba atoms and H2O molecules. Uranium exhibits (2+4)-coordination mean U-O bond lengths 1.78 A the uranyl oxygens 2.28 phosphate oxygens. average P-O length 1.52 A. Barium coordinated two five water Ba−O vary from 2.74 to 3.11 Two six molecules formula not bonded barium.