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 [Cd1–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). A group of new tellurite halides, CdSm2(TeO3)2Cl4, CdEu2(TeO3)2Cl4, and CdGd2(TeO3)2Cl4, adopt layered structures corresponding to sequences of [Ln12(TeO3)12]12+ and edge‐sharing CdCl6 octahedra not previously known among selenites and tellurites.