KThSb₂Se₆ and BaLaBi₂Q₆ (Q = S, Se) Adopt a New Structure Type Stabilized with Dichalcogenide Groups

The quaternary isostructural compounds KThSb2Se6 and BaLaBi2Q6 (Q = S, Se) were prepared. The structure type contains dichalcogenide ions, Q22- (Q = S, Se). The coordination geometry around the Th/La atoms is best described as a tricapped trigonal prism. The Th/La atoms form one-dimensional infinite double chains parallel to the [100] direction. The dichalcogenide ligand plays an important role in the construction of this double chain bridging two single chains composed of ThSe6/LaS6 prisms.