Ternary metal-rich TaNbS at high temperatures

Two new ternary metal-rich compounds, Nb21-xTaxS8 and NbxTa2-xS, isostructural with the binary metal-rich compounds Nb21S8 and Ta2S respectively, were prepared by means of high temperature techniques in the ternary Ta-Nb-S system. Single-crystal structure refinements were carried out for crystals of Nb21-xTaxS8 (R/Rw=0.027/0.043) and NbαTa2–αS (R/Rw=0.040/0.043), and the compositions were determined as Nb14.8Ta6.2S8 and Nb0.20Ta1.80S respectively from the structure refinements. Stoichiometric ranges of ternary solid-solution-type metal-rich compounds found in the Ta-Nb-S system were determined. Common structural features of these metal-rich compounds are discussed.