Thermochemistry on Coordination Behavior of Neodymium Chloride Hydrate with Diethylammonium Diethyldithiocarbamate

The complex of neodymium chloride lower hydrate with diethylammonium diethyldithiocarbamate (D-DDC) was synthesized conveniently in absolute alcohol and dry N_2 atmosphere. The title complex was identified as Et_2NH_2[Nd(S_2CNEt_2)_4] by chemical and elemental analyses and the bonding characteristics of which was characterized by IR. The enthalpies of solution of neodymium chloride hydrate and D-DDC in absolute alcohol at 298.15 K and the enthalpies change of liquid-phase reaction of formation for Et_2NH_2[Nd (S_2CNEt_2)_4] at different temperatures were determined by microcalorimetry. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of liquid-phase reaction of formation were obtained. The enthalpy change of the solid-phase title reaction at 298.15 K was calculated by a thermochemical cycle.

THE MECHANISM OF ELECTROREDUCTION OF NEODYMIUM IN MOLTEN CHLORIDES

The cathodic reduction of neodymium ion has been studied using voltammetry and chronopotentiometry methods in KCl-NaCl-NdCl_3 melt saturated by metallic neodymium.The electrode reaction of cathodic re- duction of Nd ion has been found to be Nd^2++2e→Nd in this molten salt system,and the reaction is a rever- sible and diffusion-controlled process.The electrochemical reduction potential of Nd is about-3.2V(versus chlorine reference electrode).

Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoline

Two coordinate reactions, NdCl 3·6H 2O(s) +3CCl 3COOH(s)( or TCA) =Nd(TCA) 3·3H 2O(s) +3HCl(g) +3H 2O(l) and Nd(TCA) 3·3H 2O(s) +2C 9H 7NO(s)= Nd(TCA)(C 9H 6NO) 2 (s) +2CCl 3COOH(s) +3H 2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol·L -1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol·L -1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA) 3·3H 2O,s,298.15K] and [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] are determined as Δ fH m °[Nd(TCA) 3·3H 2O,s,298.15K]= -3053.3 kJ·mol -1 and Δ fH m° [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] = -1355.6 kJ·mol -1 .

Study of NdCl_3-FeCl_3-Graphite Intercalation Compounds by X-Ray Photoelectron Spectroscopy

NdCl 3 FeCl 3 graphite intercalation compounds were synthesized by molten salt exchange method. The state of the intercalates and the relative contents of Nd, Fe, Cl, C in the product were determined by X ray photoelectron spectroscopy(XPS). From the XPS data, it is concluded that the binding energy of Fe2p electrons is about 711 20～710 3 eV, the binding energy of Nd3d electrons is about 983 08～983 20 eV, and Fe in the product has two valence states (Fe 3+ and Fe 2+ ).

Thermokinetics on the Reaction of Formation of the Ternary Complex Nd[(C_5H_8NS_2)_3(C_(12)H_8N_2)]

The title ternary complex Nd[(C5H8NS2)3(C12H8N2)] has been synthesized in absolute ethanol by the reaction of NdCl33.74H2O with ammonium pyrrolidinyldithiocarboxylate (APDC) and 1,10-phenanthroline (phenH2O) at air atmosphere without any cautions against moisture. The bonding characteristics of the complex were characterized by IR, showing that Nd3+ is bonded with sulfur atom in the APDC and coordinated with nitrogen atom in the phen. TG-DTG investigation indicates that the title complex was decomposed into Nd2S3 and deposited carbon in one step where Nd2S3 predominated in the final products. The enthalpy change of formation of the reaction on the title com-plex in liquid-phase has been determined by a microcalorimeter. Thermodynamic parameters (the activation en-thalpy, the activation entropy and the activation free energy) and kinetics parameters (the rate constant, the apparent activation energy, the pre-exponential constant and the reaction order) of the title reaction have been calculated. The enthalpy change of the solid-phase reaction has been obtained by a thermochemistry cycle.