Fig. 2.

Reaction maps obtained from sequential refinements to in situ diffraction data. (A) Reactions of Cu + K₂S₃ lead to formation of KCu₃S₂ and the new phase K₃Cu₄S₄ on heating. These dissolve into the melt upon heating, and K₃Cu₈S₆ crystallizes upon cooling. A similar phase progression occurs for Cu + 5K₂S₃ (B), with KCu₃S₂ also forming on cooling. Reactions of Cu + K₂S₅ (C) and Cu + 5K₂S₅ (D) produce the layered phase KCu₄S₃. Reactions of Sn + K₂S₃ (E) produce SnS and the new phase K₆Sn₂S₇ on heating. No ternary phases are observed for Sn + 5K₂S₃ (F). The lowest-melting reaction Sn + K₂S₅ (G) reveals formation of the new phase K₅Sn₂S₈ from a melt upon heating. K₄Sn₂S₆ and K₂Sn₂S₅ crystallize concurrently upon cooling. For Sn + 5K₂S₅ (H), the progression is similar but K₂Sn₂S₅ is absent.