Darstellung und Kristallstruktur der Dialkalimetalltrichalkogenide Rb2S3, Rb2Se3, Cs2S3 und Cs2Se3

Preparation and Crystal Structure of the Dialkali Metal Trichalcogenides Rb₂S₃, Rb₂Se₃, Cs₂S₃, and Cs₂Se₃ Crystalline products were obtained by the reaction of the pure alkali metals with the chalcogens in the molar ratio 2:3 in liquid ammonia at pressures up to 3000 bar and temperatures around 600 K. The substances crystallize in the K₂S₃ type structure (space group Cmc2₁(NO. 36)). Unit cell constants see ?Inhaltsübersicht”?. The characteristic feature of this structure are bent polyanions X₃^2?:(X = S,Se). The new described compounds are compared with the other known alkali metal trichalcogenides.