Coordination Reaction of Alanine with Neodymium(III) and Erbium(III) Nitrate. Thermochemical study

The solid-state coordination reaction: Nd(NO3)3·6H2O(s)+4Ala(s) → Nd(Ala)4(NO3)3·H2O(s)+5H2O(l) and Er(NO3)3·6H2O(s)+4Ala(s) → Er(Ala)4(NO3)3·H2O(s)+5H2O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L–1 HCl solvent of these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(Ala)4(NO3)3·H2O, s, 298.2 K] and[Er(Ala)4(NO3)3·H2O, s,298.2 K] at 298.2 K have been determined to be ΔfHm0 [Nd(Ala)4(NO3)3·H2O,s, 298.2 K]=–3867.2 kJ mol–1, and ΔfHm0 [Er(Ala)4(NO3)3·H2O, s, 298.2 K]=–3821.5 kJ mol–1.