Synthesis and structure determination of a new cerium titanium oxysulfide [Ce20Ti11S44O6]

The new compound Ce20Ti11S44O6 crystallizes in space group D2h13-Pmmn of the orthorhombic system with two formula units in a cell of dimensions a = 22.4628(8), b = 14.2531(7), and c = 10.382(2) (T= 293 K). Isostructural with La20Ti11S44O6, this compound comprises ∞2[(Ti4S2O4(TiS6)22(Ti2S10)22] layers of [Ti4S2O4] clusters linked together by edge-sharing, rutile-like chains of TiS6 octahedra. An additional pair of corner-sharing, oxygen-bridged, Ti-centered octahedra are found separated from the covalently-bonded layers. Charge balance restrictions require that Ti atoms be in the mixed oxidation states of 3+ or 4+. The seven crystallographically independent Ce atoms are found in three different coordination polyhedra.