Specific Features of the Crystal Chemistry of Layered Uranyl Compounds with the Ratio UO2: TO4=5: 8 (T = S6+, Cr6+, Se6+, Mo6+)

Two new U(VI) compounds templated with organic molecules, [(CH6N)(3)(H2O)][(CH6N)(2)(C3H10N)center dot (H2O)][(UO2)(5)(CrO4)(8)(H2O)] (1) and [(C6H10N3O3)(H5O2)(2)(H2O)][(H5O2)(3)(H2O)][(UO2)(5)(SO4)(8)(H2O)] (2), were prepared by combination of hydrothermal synthesis and isothermal evaporation methods. Compounds 1 and 2 crystallize in the monoclinic system, space group P2(1)/n, a = 21.921(5), b = 11.016(2), c = 22.021(5) , beta = 90.571(5)A degrees for 1 and P (2)/c, a = 18.1693(17), b = 10.0732(10), c = 30.098(3) , beta = 103.427(2)A degrees for 2. The reflections from the single crystals were collected at 100 K. The structures were solved by the direct methods and refined to R (1) = 0.053 and 0.070 for 1 and 2, respectively. The crystal structures of 1 and 2 are based on [(UO2)(5)(TO4)(8)(H2O)](6-) modular layers (T = S6+, Cr6+) between which protonated organic molecules, water molecules, and hydroxonium ions are located. Specific features of the crystal chemistry of U(VI) compounds with tetrahedral oxoanions with the ratio UO2: TO4 = 5: 8 (T = S6+, Cr6+, Se6+, Mo6+) are considered.