Mild Solvothermal Syntheses of Thioargentates A–Ag–S (A = K, Rb, Cs) and A–Ag–Ge–S (A = Na, Rb): Crucial Role of Excess Sulfur

A series
sulfides of A–Ag–S (1–3; A = K, Rb, Cs), Na5AgGe2S7 (4), and Rb2Ag2GeS4 (5) have been prepared solvothermally in the presence
of excess sulfur. Among these compounds, 4 is a new compound
that has a novel layered structure; the others were obtained under
mild conditions. The results showed that excess sulfur could increase
the solubility of silver sulfide and lower the synthetic temperature
effectively. The mineralizer effect of excess sulfur is discussed
in detail.