Synthesis, Characterization and Standard Molar Formation Enthalpy of [Sm(C7H5O3)2(C4H6NO2S)]•2H2O

[Sm(C7H5O3)(2)(C4H6NO2S)]center dot 2H(2)O was synthesized from the reaction of samarium chloride hexahydrate with salicylic acid and thioproline, and characterized by IR, elemental analysis and thermogravimatric analysis. The standard molar enthalpies of the solutions Of SmCl3 center dot 6H(2)O(s), 2[C7H6O3(s)], [C4H7NO2S(s)] and [Sm(C7H5O3)(2)center dot(C4H6NO2S)center dot 2H(2)O(S)] in a mixed solvent of absolute ethyl alcohol, dimethyl formamide(DMF) and 3 mol/L HCl were, respectively, determined by calorimetry to be Delta H-s(m)Theta[SmCl3 center dot 6H(2)O(s), 298.15 K]=(-46.68 +/- 0.15) kJ/mol, Delta H-s(m)Theta[2C(7)H(6)O(3)(s)] 298.15 K]=(25.19 +/- 0.02) kJ/mol, Delta H-s(m)Theta[C4H7NO2S(s), 298.15 K]=(16.20 +/- 0.17) kJ/mol and Delta H-s(m)Theta{[Sm(C7H5O3)(2)(C4H6NO2S)](center dot)2H(2)O(S), 298.15 K}=(-81.24 +/- 0.67) kJ/mol. The enthalpy change of the reaction SmCl3 center dot 6H(2)O(s)+2C(7)H(6)O(3)(S)+C4H7NO2S(S)=[Sm(C7H5O3)(2)(C4H6NO2S)]center dot 2H(2)O(s)+3HCl(g)+4H(2)O(1) was determined to be Delta H-r(m)Theta=(123.45 +/- 0.71) kJ/mol. From the data in the literature, the standard molar formation enthalpy of [Sm(C7H5O3)(2)(C4H6NO2S)]center dot 2H(2)O(s) was estimated to be Delta fH(m)(Theta){[Sm(C7H5O3)(2)(C4H6NO2S)]center dot 2H(2)O(s) 298.15 K}= (-2912.03 +/- 3.1) kJ/mol through Hess' law.