The combustion energies have been determined for the solid complexes, RE(Met) 4(NO 3) 3·6H 2O(RE=La～Nd, Sm～Lu), by means of a rotating bombicalorimeter. The standard enthalpies of combustion, ΔH ...The combustion energies have been determined for the solid complexes, RE(Met) 4(NO 3) 3·6H 2O(RE=La～Nd, Sm～Lu), by means of a rotating bombicalorimeter. The standard enthalpies of combustion, ΔH c,coor(s) , and standard enthalpies of formation, ΔH f,coor(s) , have been calculated for these complexes. It has been found that “tetrad effect” regularity was observed for the fact that the standard enthalpies of formation are ploted against the atomic numbers of the elements in lanthanide series. The results show that a certain amount of covalency is present for chemical bond between the rare earth cation and methionine.展开更多
Four solid ternary complexes of RE (C_5H_8NS_2)_3(C_(12)H_8N_2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamat...Four solid ternary complexes of RE (C_5H_8NS_2)_3(C_(12)H_8N_2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamate (APDC) and 1, 10-phenanthroline·H_2O (o-phen·H_2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes show that the RE^(3+) coordinated with six sulfur atoms of three PDC^- and two nitrogen atoms of o-phen·H_2O. It was assumed that the coordination number of RE^(3+) is eight. The constant-volume combustion energies of the complexes, Δ_cU, were determined as (-16937 88±9 79 ), (-17588 79±8 62 ), ((-17747 14±)8 25 ) and (-17840 37±8 87 ) kJ·mol^(-1), by a precise rotating-bomb calorimeter at 298.15 K. Its standard molar enthalpies of combustion, Δ_cH~θ_m, and standard molar enthalpies of formation, Δ_fH~θ_m, were calculated as (-16953 37±9 79), (-17604 28±8 62), (-17762 63±8 25), (-17855 86±8 87) kJ·mol^(-1) and (-857.04±10.52), (-282.43±9.58), (-130.08±9.13), (-55.75±9.83) kJ·mol^(-1).展开更多
The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title ...The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.展开更多
Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE（HSal）3·2H2O（RE = La...Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE（HSal）3·2H2O（RE = La, Ce, Pr, Nd, Sm） by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE^3＋ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry （CV）. It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes,△c U, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, △cH^θm, and standard molar enthalpies of formation, △fH^θm, were calculated.展开更多
The combustion energy has been determined for the nine solid complexes of rare earth perchlorate with glycine and imidazole using a rotatingbomb calorimeter.The standard enthalpy of combustion,H0 -c,coor(s), and stan...The combustion energy has been determined for the nine solid complexes of rare earth perchlorate with glycine and imidazole using a rotatingbomb calorimeter.The standard enthalpy of combustion,H0 -c,coor(s), and standard enthalpy of formation,H0 -f,coor(s), for these complexes have been calculated. From the plot of standard enthalpy of formation versus atomic number of the elements in lanthanide series the tripartite effect regularity was observed and the unknown standard enthalpy of formation for similar complexes,Ce(Gly)4(Im)(ClO4)32H2O and Pm(Gly)4(Im)(ClO4)32H2O,can be estimated according to the figure.展开更多
文摘The combustion energies have been determined for the solid complexes, RE(Met) 4(NO 3) 3·6H 2O(RE=La～Nd, Sm～Lu), by means of a rotating bombicalorimeter. The standard enthalpies of combustion, ΔH c,coor(s) , and standard enthalpies of formation, ΔH f,coor(s) , have been calculated for these complexes. It has been found that “tetrad effect” regularity was observed for the fact that the standard enthalpies of formation are ploted against the atomic numbers of the elements in lanthanide series. The results show that a certain amount of covalency is present for chemical bond between the rare earth cation and methionine.
基金Project supported by the Natural Science Foundation of China (2047104) and the Natural Science Foundation of Shaanxi Province (2003B19)
文摘Four solid ternary complexes of RE (C_5H_8NS_2)_3(C_(12)H_8N_2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamate (APDC) and 1, 10-phenanthroline·H_2O (o-phen·H_2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes show that the RE^(3+) coordinated with six sulfur atoms of three PDC^- and two nitrogen atoms of o-phen·H_2O. It was assumed that the coordination number of RE^(3+) is eight. The constant-volume combustion energies of the complexes, Δ_cU, were determined as (-16937 88±9 79 ), (-17588 79±8 62 ), ((-17747 14±)8 25 ) and (-17840 37±8 87 ) kJ·mol^(-1), by a precise rotating-bomb calorimeter at 298.15 K. Its standard molar enthalpies of combustion, Δ_cH~θ_m, and standard molar enthalpies of formation, Δ_fH~θ_m, were calculated as (-16953 37±9 79), (-17604 28±8 62), (-17762 63±8 25), (-17855 86±8 87) kJ·mol^(-1) and (-857.04±10.52), (-282.43±9.58), (-130.08±9.13), (-55.75±9.83) kJ·mol^(-1).
文摘The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.
基金Project supported bythe Northwest University (02NW02) and the Educational Committee of Shaanxi Province (05JC31)
文摘Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE（HSal）3·2H2O（RE = La, Ce, Pr, Nd, Sm） by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE^3＋ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry （CV）. It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes,△c U, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, △cH^θm, and standard molar enthalpies of formation, △fH^θm, were calculated.
文摘The combustion energy has been determined for the nine solid complexes of rare earth perchlorate with glycine and imidazole using a rotatingbomb calorimeter.The standard enthalpy of combustion,H0 -c,coor(s), and standard enthalpy of formation,H0 -f,coor(s), for these complexes have been calculated. From the plot of standard enthalpy of formation versus atomic number of the elements in lanthanide series the tripartite effect regularity was observed and the unknown standard enthalpy of formation for similar complexes,Ce(Gly)4(Im)(ClO4)32H2O and Pm(Gly)4(Im)(ClO4)32H2O,can be estimated according to the figure.
