Abstract: There is provided a process for preparing compounds of formula M3M1A2. The process comprises reacting a compound of formula M2M1A2 with a compound of formula M3X2, in the presence of at least one coordinating solvent. M1 can be chosen from B3+, Al3+, Ga3+, In3+, Tl3+, Fe3+, and Au3+; M2 can be chosen from Li+, Na+, K+, Cs+, (T1)3Si—, and N(T2)4+; M3 can be chosen from Cu+, Ag+, Li+, Na+, K+, Cs+, Rb+, Fr+, Au+, and Hg+; A can be chosen from S and Se; and X2 can be chosen from Cl?, Br?, I?, F?, CH3COO?, NO3?, and CN?. Such compounds can be used for various purposes in the field of electrochemistry.