A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with releva...A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be： （308.73±0.45） K, （10.49±0.05） kJ·mol^-1 and （33.9±0.2） J·K^-1·mol^-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method. Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O（s）＋2L-Glu（s）＋6NaClO4·H2O（s）] and the mixture {[Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）＋6NaCl（s）} in 100 mL of 2 mol·dm^-3 HClO4 as calorimetric solvent, and {2HClO4（1）} in the solution A＇ at T=298.15 K were measured to be, △dHm,1=（31.552±0.026） kJ·mol^-1, △dHm,2 = （41.302±0.034） kJ·mol^-1, and △dHm,3 = （ 14.986 ± 0.064） kJ·mol^-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fHm-=-（7551.0±2.4） kJ·mol^-1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.展开更多
Crystal of rare earth perchlorate complex compound with proline was synthesized. By using TG, DTA and chemical analytic method, and comparing with relative literatures, its structure was characterized as [Gd2(Pro)6(H2...Crystal of rare earth perchlorate complex compound with proline was synthesized. By using TG, DTA and chemical analytic method, and comparing with relative literatures, its structure was characterized as [Gd2(Pro)6(H2O)4](ClO4)6, and it has a purification of 99.0% . A thermochemical cycle was designed at 298.15K, measurements of solution calorimetry of the reactants [2GdCl3· 6H2O+ 6Pro+ 6NaClO4· H2O] and the products {[Gd2(Pro)6(H2O)4](ClO4)6+ 6NaCl} were carried out in an isoperibel reaction calorimeter, respectively. The calorimetric solvent used was 2mol· L- 1 HCl. The chemical reaction and standard enthalpy of formation were calculated as:<IMG SRC="IMAGE/12180047.JPG" HEIGHT=11 WIDTH=24> =- 46.829kJ· mol- 1,<IMG SRC="IMAGE/12180048.JPG" HEIGHT=11 WIDTH=24> ([Gd2(Pro)6(H2O)4](ClO4)6,s,298.15K)=- 6532.745kJ· mol- 1.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20673050）.
文摘A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be： （308.73±0.45） K, （10.49±0.05） kJ·mol^-1 and （33.9±0.2） J·K^-1·mol^-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method. Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O（s）＋2L-Glu（s）＋6NaClO4·H2O（s）] and the mixture {[Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）＋6NaCl（s）} in 100 mL of 2 mol·dm^-3 HClO4 as calorimetric solvent, and {2HClO4（1）} in the solution A＇ at T=298.15 K were measured to be, △dHm,1=（31.552±0.026） kJ·mol^-1, △dHm,2 = （41.302±0.034） kJ·mol^-1, and △dHm,3 = （ 14.986 ± 0.064） kJ·mol^-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fHm-=-（7551.0±2.4） kJ·mol^-1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.
文摘Crystal of rare earth perchlorate complex compound with proline was synthesized. By using TG, DTA and chemical analytic method, and comparing with relative literatures, its structure was characterized as [Gd2(Pro)6(H2O)4](ClO4)6, and it has a purification of 99.0% . A thermochemical cycle was designed at 298.15K, measurements of solution calorimetry of the reactants [2GdCl3· 6H2O+ 6Pro+ 6NaClO4· H2O] and the products {[Gd2(Pro)6(H2O)4](ClO4)6+ 6NaCl} were carried out in an isoperibel reaction calorimeter, respectively. The calorimetric solvent used was 2mol· L- 1 HCl. The chemical reaction and standard enthalpy of formation were calculated as:<IMG SRC="IMAGE/12180047.JPG" HEIGHT=11 WIDTH=24> =- 46.829kJ· mol- 1,<IMG SRC="IMAGE/12180048.JPG" HEIGHT=11 WIDTH=24> ([Gd2(Pro)6(H2O)4](ClO4)6,s,298.15K)=- 6532.745kJ· mol- 1.
