DOUBLE CERIUM(III) CERIUM(IV) SULFATE K5CE2(SO4)6.H2O

The crystal structure of the double cerium(III) cerium(IV) sulfate with the composition K5Ce2(SO4)6.H2O has been studied (CAD4 apparatus, Mo radiation, 3235 reflections R = 0.025, R(w) = 0.017): a = 17.688(1), b = 7.0277(7), c = 19.411(3) angstrom, beta = 112.03(1)-degrees, Z = 4, space group Cc. The crystals have a layer structure; the spaces between the {K2Ce2(SO4)6}2 infinity 3n layers are occupied by potassium cations and the water molecule, whose H-bonds help to hold the layers together. The distribution of Ce(III) and Ce(IV) in the two independent Ce-polyhedra forming the [Ce2O16] dimer has been examined. The structure of K5Ce2(SO4)6.H2O is a distortion of the idealized controsymmetric version (space group C2/c); the reasons for the acentric nature of the structure of the double sulfate have been discussed.