THERMAL-DECOMPOSITION AND SOLUTION CALORI METRY OF AMMONIUM SAMARIUM CHLORIDES

We determined the decomposition equilibria of ammonium samarium chlori des (NH4)(2)SmCl5 and NH4Sm2Cl7 by total pressure measurements and der ived their thermodynamical data from the decomposition functions. The enthalpies of formation were compared with the results of the solution calorimetry. The heats of solution of all solid phases in the system SmCl3-NH4Cl and of Sm2O3 were measured in 4n HCl. The enthalpies of fo rmation of ammonium samarium chlorides were derived from the enthalpie s of formation of SmCl3 and of NH4Cl and their heats of solution.