|(übersetzt):||This work deals with the preparation and characterization of new multinary niobium and tantalum polychalcogenides. The products were synthesized using the "reactive flux method" at temperatures between 300 and 500°C. Five new compounds A6M4S22 (with A = K for M = Nb and A = K, Rb, Cs for M = Ta) and two compounds Rb6M4S25 (with M = Nb, Ta) were synthesized as red orange single crystals. K6Ta4S22 was found in two different modifcations. The structure of all compounds consists of M2S11 units as fundamental building units which are linked by terminal sulfur ligands to the dimeric anions [M4S22]6- or via a S3 chain to the [M4S25]6- anions. The anions build stacks which are separated by the alkalimetal cations. The compounds were characterized using X-ray diffraction methods, EDX, DSC as well as MIR, Raman and UV-Vis spectroscopy. One important result of the thermal investigations is the possibility to synthesize the compounds Rb6M4S22 by degradation of Rb6M4S25 (M = Nb, Ta). Furthermore the new quaternary niobium compound BaKNbS4 was prepared. The structure consists of NbS4 tetrahedra and barium and potassium cations.
|Schlagworte:||Tantalchalkogenide ; Niobchalkogenide ; Multinäre Verbindungen ; Kristallchemie , crystal structure, polychalcogenides, X-ray diffraction, powder pattern, reactive flux, solid state chemistry, tantalum polysulfides, niobium polysulfides , thermal investigations, spectroscopic investigations