'White powdery tungstic acid' has been used for preparing various types of tungsten-containing compounds due to its high reactivity. The present paper covers the standard molar enthalpies of formation, △H0/f ...'White powdery tungstic acid' has been used for preparing various types of tungsten-containing compounds due to its high reactivity. The present paper covers the standard molar enthalpies of formation, △H0/f of three tungsten- containing acids. The values found for 'white powdery tungstic acid' WO3·1. 68H2O, 'yellow tungstic acid' WO3·1. 20H2O and dodecatungstophosphoric acid H3(PW12O40)·25H2O at 298. 15 K were-(1312±1), - (1192±1) and -(18150±13) kJ mol-1, respectively.展开更多
Bioactive glasses in the system SiO2-Na2O-CaO-P2O5 were prepared by the conventional melting process at a high temperature in an electric furnace. The densities of the glasses as well as their glass transition tempera...Bioactive glasses in the system SiO2-Na2O-CaO-P2O5 were prepared by the conventional melting process at a high temperature in an electric furnace. The densities of the glasses as well as their glass transition temperatures were measured experimentally. Also, the glasses were characterized by solution calorimetry at 298 K in an acidic solvent consisting of HF (6 M) and HNO3 (4 M). A simulation of the bioactivity properties of these obtained glasses was carried out by thermodynamic calculations, with the purpose of understanding the in vitro results obtained.展开更多
In order to obtain the standard molar enthalpies of formation of Rare-Earth amino acid coordination compounds, precise isothermal solution-reaction calorimetric method was used. The value of Δ-rHΘ-m of two coordinat...In order to obtain the standard molar enthalpies of formation of Rare-Earth amino acid coordination compounds, precise isothermal solution-reaction calorimetric method was used. The value of Δ-rHΘ-m of two coordination reactions was determined at T = 298.2 K. From the experimental results and other auxiliary values, the standard molar enthalpies of formation of Ln(Gly)- 5/2(Ala)- 3/2 (ClO-4)-3·H-2O(s) [Ln = La, Yb] at T = 298.2K were obtained. The values of them is to be Δ-rHΘ-m [La(Gly)- 5/2(Ala)- 3/2(ClO-4)-3·H-2O(s)] =-3545.45 kJ/ mol and Δ-rHΘ-m [Yb(Gly)- 5/2(Ala)- 3/2(ClO-4)-3·H-2O(s)]= -3793.81kJ/mol, respectively.展开更多
A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B ...A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B 2O(OH) 6]·H 2O. The enthalpy of solution of MgO·B 2O 3·4H 2O in HCl (1.0492 mol·L -1) was determined. With the incorporation of the standard molar enthalpies of formation of MgO (s), H 3BO 3 (s), and H 2O (l), the standard molar enthalpy of formation of -(3135.31±1.68) kJ·mol -1 of MgO·B 2O 3·4H 2O was obtained. Thermodynamic properties of this compound were also calculated by group contribution method.展开更多
文摘'White powdery tungstic acid' has been used for preparing various types of tungsten-containing compounds due to its high reactivity. The present paper covers the standard molar enthalpies of formation, △H0/f of three tungsten- containing acids. The values found for 'white powdery tungstic acid' WO3·1. 68H2O, 'yellow tungstic acid' WO3·1. 20H2O and dodecatungstophosphoric acid H3(PW12O40)·25H2O at 298. 15 K were-(1312±1), - (1192±1) and -(18150±13) kJ mol-1, respectively.
文摘Bioactive glasses in the system SiO2-Na2O-CaO-P2O5 were prepared by the conventional melting process at a high temperature in an electric furnace. The densities of the glasses as well as their glass transition temperatures were measured experimentally. Also, the glasses were characterized by solution calorimetry at 298 K in an acidic solvent consisting of HF (6 M) and HNO3 (4 M). A simulation of the bioactivity properties of these obtained glasses was carried out by thermodynamic calculations, with the purpose of understanding the in vitro results obtained.
基金FundedbytheTeachingandResearchAwardProgramforOutstandingYoungProfessorsinHighEducationInstitute MinistryofEducation P .R .China
文摘In order to obtain the standard molar enthalpies of formation of Rare-Earth amino acid coordination compounds, precise isothermal solution-reaction calorimetric method was used. The value of Δ-rHΘ-m of two coordination reactions was determined at T = 298.2 K. From the experimental results and other auxiliary values, the standard molar enthalpies of formation of Ln(Gly)- 5/2(Ala)- 3/2 (ClO-4)-3·H-2O(s) [Ln = La, Yb] at T = 298.2K were obtained. The values of them is to be Δ-rHΘ-m [La(Gly)- 5/2(Ala)- 3/2(ClO-4)-3·H-2O(s)] =-3545.45 kJ/ mol and Δ-rHΘ-m [Yb(Gly)- 5/2(Ala)- 3/2(ClO-4)-3·H-2O(s)]= -3793.81kJ/mol, respectively.
文摘A new magnesium borate MgO·B 2O 3·4H 2O was synthesized by the method of phase transformation of double salt and characterized by XRD, IR spectra and TG. The structural formula of this compound was Mg[B 2O(OH) 6]·H 2O. The enthalpy of solution of MgO·B 2O 3·4H 2O in HCl (1.0492 mol·L -1) was determined. With the incorporation of the standard molar enthalpies of formation of MgO (s), H 3BO 3 (s), and H 2O (l), the standard molar enthalpy of formation of -(3135.31±1.68) kJ·mol -1 of MgO·B 2O 3·4H 2O was obtained. Thermodynamic properties of this compound were also calculated by group contribution method.
