Synthesis, characterization and standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H6NO)

The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C7H5O3)2·(C9H6NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [NdCl3·6H2O(s)], [2C7H6O3(s)], [C9H7NO(s)] and [Nd(C7H5O3)2·(C9H6NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at 298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction (1)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ NdCl_3 \cdot 6H_2 O(s) + 2C_7 H_6 O_3 (s) + C_9 H_7 NO(s) = Nd(C_7 H_5 O_3 )_2 \cdot (C_9 H_6 NO)(s) + 3HCl(g) + 6H_2 O(l) $$\end{document} was determined to be ΔrHmΘ=117.89±0.37 kJ mol−1. From data in the literature, through Hess’ law, the standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H7NO)(s) was estimated to be ΔfHmΘ[Nd(C7H5O3)2·(C9H6NO)(s), 298.15 K]=−2031.80±8.6 kJ mol−1.