The crystal chemistry of the zippeite group

Single crystals of eight zippeite-group compounds have obtained using mild hydrothermal synthesis techniques. The structure of each has been determined with single-crystal diffraction data collected using MoKalpha X-radiation and an APEX CCD-based detector, and refined on the basis of P for all unique data. The structure of zippeite, K-3(H2O)(3)[(UO2)(4)(SO4)(2)O-3(OH)], is monoclinic, C2, a 8.7524(4), b 13.9197(7), c 17.6972(8) Angstrom, beta 104.178(1)degrees, V2090.39(17) Angstrom(3), RI 3.30%, D-c 4.794 g/cm(3). The structure of sodium-zippeite, Na-5(H2O)(12)[(UO2)(8)(SO4)(4)O-5(OH)(3)], is monoclinic, P2(1)/n, a 17.6425(11), b 14.6272(9), c 17.6922(11) Angstrom, beta 104.461(1)degrees, V 4421.0(5) Angstrom(3), R1 6.88%, D-c 4.517 g/cm(3). The structure of magnesium-zippeite, Mg(H2O)(3.5)[(UO2)(2)(SO4)O-2], is monoclinic, C2/m, a 9.6514(4), b 14.1938(7), c 17.7211(9) Angstrom, beta 104.131(1)degrees, V 2110.24(18) Angstrom(3), R1 2.39%, D-c 4.756 g/cm(3). The structure of zinc-zippeite, Zn(H2O)(3.5)[(UO2)(2)(SO4)O-2], is monoclinic, C2/m, a 8.6437(10), b 14.1664(17), c 17.701(2) Angstrom, beta 104.041(3)degrees, V2102.7(4) Angstrom(3), R1 4.57%, D-c 5.032 g/cm(3). The structure of cobalt-zippeite, Co(H2O)(3.5)[(UO2)(2)(SO4)O-2], is monoclinic, C2/m, a 8.650(4), b 14.252(9), c 17.742(10) Angstrom, beta 104.092(19)degrees, V 2122(2) Angstrom(3), R1 5.55%, D-c 4.948 g/cm(3). The structure of (NH4)(4)(H2O)[(UO2)(2)(SO4)O-2](2) is monoclinic, C2/m, a 8.6987(15), b 14.166(2), c 17.847(3) Angstrom, 0 104.117(4)degrees, V 2132.9(3) Angstrom(3), R1 4.31%, D-c 4.442 g/cm(3). The structure of (NH4)(2)[(UO2)(2)(SO4)O-2] is orthorhombic, Cmca, a 14.2520(9), b 8.7748(5), c 17.1863(10) Angstrom, V 2149.3(2) Angstrom(3), R1 5.11%, D-c 4.353 g/cm(3). The structure of Mg-2(H2O)(11)[(UO2)(2)(SO4)O-2](2) is monoclinic, P2(1)/c, a 8.6457(4), b 17.2004(8), c 18.4642(9) Angstrom, beta 102.119(1)degrees, V2684.6(2) Angstrom(3), R1 4.73%, D-c 3.917 g/cm(3). Each structure contains the zippeite-type sheet consisting of chains of edge-sharing uranyl pentagonal bipyramids that are cross-linked by vertex sharing with sulfate tetrahedra, although the compositional details of the sheet are varied. The interlayer configurations are diverse, and are related to the bonding requirements of the sheets.