In this, article we compare and contrast the evolution of ternary modulated reactants of the form M-Mo-Se (M = Ni, Zn, Sn, In, and Cu) with each other and with the binary Mo-Se system. The binary elementally modulated reactants interfacially nucleate MoSe2 over a broad composition range surrounding that of the binary compound Mo6Se8. Increasing the concentration of any of the studied ternary elements except nickel above a critical value in the initial reactant suppressed interfacial nucleation of the diselenide. The nickel-containing reactants all inter-facially nucleated NixMoSe2 at low temperatures. The subsequent nucleation and growth of crystalline compounds from the amorphous intermediates obtained in the other four systems was found to depend on both the identity and concentration of the ternary element. In the Sn-Mo-Se system, a layered dichalcogenide was the first compound nucleated. In the Zn-Mo-Se system, the dichalcogenide and the ternary compound ZnxMo6Se8 were observed to nucleate at approximately the same temperature. In the copper- and indium-containing systems, the cluster-containing compounds, CuxMo6Se8 and In3.33+/-deltaMo15Se19, were observed to be the first crystalline compounds formed. Annealing all four of these systems at temperatures greater than 1100 degrees C resulted in the growth of Chevrel phase compounds at the expense of molybdenum diselenide.