Thermodynamic Properties of Nd(Gly)2Cl3•3H2O and Pr(Ala)3Cl3•3H2O

The heat capacities of rare earth complexes, Nd(Gly)(2)Cl-3 center dot 3H(2)O and Pr(Ala)(3)Cl-3 center dot 3H(2)O were measured with a high-precision automatic adiabatic calorimeter in the temperature range from 80 to 357 K for Nd(Gly)(2)Cl-3 center dot 3H(2)O, and from 80 to 374 K for Pr(Ala)(3)Cl-3 center dot 3H(2)O. The thermodynamic functions (H-T-H-298.15) and (S-T-S-298.15) relative to the reference temperature 298.15 K of the two compounds were calculated based on experimental heat capacity data. Possible mechanisms of thermal decompositions were proposed according to the thermogravimetric (TG) analysis. Based on the measurements of dissolution enthalpies using a solution-reaction isoperibol calorimeter, the standard molar enthalpies of formation were calculated in terms of a designed Hess thermochemical cycle.