Xanthate complexes are used in the low temperature atom efficient synthesis of some geological and technologically important ternary compounds. The process involves direct heating of a stoichiometric mixture of the metal xanthate complexes. The reactive melts of the xanthates, generated in the transition state, cleanly decompose to ternary metal sulfides. The method has great potential for the facile scalable synthesis of ternary materials of composition ABX2 (such as AI = Ag, Cu; BIII = Bi, Cr, Fe, In, Sb and X = S) or AB2X4 (AII = Cd, Co, Cu, Ni; BIII = Co, Cr, Ni, Fe, and X = S).