Novel cesium cerium(iv) iodate Cs2Ce(IO3)6: hydrothermal synthesis, crystal structures and thermal stability

Abstract

New cesium cerium(IV) iodate Cs₂Ce(IO₃)₆ was successfully prepared by applying a hydrothermal technique from starting reagents CsF, CeO₂, H₅IO₆ and HIO₃ at 230 °C. Cs₂Ce(IO₃)₆ was analyzed via single crystal and powder XRD, EDX, IR spectroscopy and thermal analysis. The new compound crystallizes in the monoclinic space group C2/c with a = 14.0652(3) Å, b = 8.1890(2) Å, c = 17.7211(4) Å, β = 103.601(2)°, V = 1983.99(8) ų, and Z = 4. The crystal structure of Cs₂Ce(IO₃)₆ consists of CeO₈ square antiprisms sharing their apexes and edges with trigonal pyramidal IO₃⁻ groups to form layers [Ce(IO₃)₆]²⁻ parallel to the ab plane. These layers are further stabilised by a 12-vertex polyhedron, CsO₁₂, situated in their voids. The IR spectrum of Cs₂Ce(IO₃)₆ displays iodate group bands. According to DTA analysis, cesium cerium(IV) iodate exhibits high thermal stability in the air at temperatures up to 414 °C.