Synthesis, characterization and standard molar enthalpy of formation of Sm(C 7H 5O 3) 2·(C 9H 6NO)

Abstract

The complex of bis(salicylato)hydroxyquinolinosamarium(III), Sm(C 7H 5O 3) 2·(C 9H 6NO), was synthesized and characterized by IR, elemental analysis, molar conductance and thermogravimetric analysis. The standard molar enthalpies of solution of [SmCl 3·6H 2O(s)], [2C 7H 6O 3(s)], [C 9H 7NO(s)] and [Sm(C 7H 5O 3) 2·(C 9H 6NO)(s)] in the calorimetric solvent (a mixed solution consisting of absolute ethyl alcohol, dimethyl formamide (DMF) and perchloric acid were determined by solution-reaction calorimetry at 298.15 K, respectively. The enthalpy of the reaction (1) SmC l 3 ⋅ 6 H 2 O ( s ) + 2 C 7 H 6 O 3 ( s ) + C 9 H 7 NO ( s ) = Sm ( C 7 H 5 O 3 ) 2 ⋅ ( C 9 H 6 NO ) ( s ) + 3 HCl ( g ) + 6 H 2 O ( l ) was determined to be Δ r H m ° = 89.59 ± 0.18 kJ mo l − 1 . According to the above results and the data given in literature, through Hess’ law, the standard molar enthalpy of formation of Sm(C 7H 5O 3) 2·(C 9H 7NO)(s) was estimated to be Δ f H m ° [Sm(C 7H 5O 3) 2·(C 9H 6NO)(s), 298.15 K] = −2055.9 ± 3.03 kJ mol −1.