Ten new complex compounds of general formula [M(Phen)x] [Ag(CN)2]·nH2O(M=Fe, Mn, Ni, Cu, Zn and Cd; x=2 or 3; n=1, 2, or 3) were prepared and studied by TG-DTA. A comparison of the thermal stabilities of these compounds showed that the complexes containing three molecules of phenanthroline exhibit lower thermal stability than the corresponding complexes containing two molecules of phenanthroline.