Rare-earth cadmium tellurite chlorides with a structural type exhibiting [Ln₁₂(TeO₃)₁₂] slabs alternating with CdCl₆ octahedral layers

A series of new rare-earth cadmium metal tellurite chlorides were synthesized by the salt flux technique and characterized by single-crystal X-ray diffraction. The new compounds CdSm₂(TeO₃)₂Cl₄ (I), CdEu₂(TeO₃)₂Cl₄ (II), and CdGd₂(TeO₃)₂Cl₄ (III), adopt layered structures corresponding to sequences of metal oxide [LnTeO₃] and metal halide [Cd_1-xCl₃] layers. They expand the known family of 2D rare-earth selenium oxyhalides into the realm of tellurium(IV) compounds and add a new targeted structure type involving rock salt slabs formed by edge-sharing CdCl₆ octahedra. The major differences in the structures of Se and Te compounds lie in the composition of the cationic slabs {[Ln₁₁(SeO₃)₁₂]⁹⁺ vs. [Ln₁₂(TeO₃)₁₂]¹²⁺} and symmetry (orthorhombic for selenites vs. tetragonal for tellurites). (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)