Values of electromotive force of the cell without liquid junction Li-ISE vertical bar Li2B4O7(m(A))(aq.), MgCl2(m(B))(aq.) vertical bar AgCl/Ag were determinaed at 298.15 K. The mean activity coefficients of LiCl in the system with ionic strengths from 0.05 to 3 mol(.)kg(-1) at different ionstrength fraction Y-B of MgCl2 have been calculated, together with the tendencies of these values along with the ion strengths and the concentrations of Mg2+ and B4O72- of the system. While the ion interaction model was studied, the experimental data were not only from this electromotive force study for Li2B4O7-MgCl2-H2O system, but also from the isopiestic studies for systems Li2B4O7-MgCl2-H2O, Li2B4O7-LiCl-H2O and Li2B4O7-H2O. The species of boric acid H3BO3 and borate anions B(OH)(4)(-), B3O3(OH)(4)(-) and B4O5(OH)(4)(2-) have been taken into account in different total boron concentrations. To consider the stoichiometric molality equilibrium constants for the formation of the aqueous species containing boron, Pitzer's osmotic equation and activity equation have been modified slightly to represent the system, and the ion interaction parameters have been obtained using multiple regression analysis. The standard deviation of the calculated and experimentally determined activity coefficients of LiCl in Li2B4O7-MgCl2-H2O system was 0.0167, which reflects that the set up model for the system with boron was adaptable to this four ion system. Values of electromotive force of the cell without liquid junction Li-ISE vertical bar Li2B4O7(m(A))(aq.), MgCl2(m(B))(aq.) vertical bar AgCl/Ag were determinaed at 298.15 K. The mean activity coefficients of LiCl in the system with ionic strengths from 0.05 to 3 mol(.)kg(-1) at different ionstrength fraction Y-B of MgCl2 have been calculated, together with the tendencies of these values along with the ion strengths and the concentrations of Mg2+ and B4O72- of the system. While the ion interaction model was studied, the experimental data were not only from this electromotive force study for Li2B4O7-MgCl2-H2O system, but also from the isopiestic studies for systems Li2B4O7-MgCl2-H2O, Li2B4O7-LiCl-H2O and Li2B4O7-H2O. The species of boric acid H3BO3 and borate anions B(OH)(4)(-), B3O3(OH)(4)(-) and B4O5(OH)(4)(2-) have been taken into account in different total boron concentrations. To consider the stoichiometric molality equilibrium constants for the formation of the aqueous species containing boron, Pitzer's osmotic equation and activity equation have been modified slightly to represent the system, and the ion interaction parameters have been obtained using multiple regression analysis. The standard deviation of the calculated and experimentally determined activity coefficients of LiCl in Li2B4O7-MgCl2-H2O system was 0.0167, which reflects that the set up model for the system with boron was adaptable to this four ion system.
Zhang, AY,Yao, Y. Thermodynamic studies by electromotive force method and ion interactionmodel for Li2B4O7-MgCl2-H2O system at 298.15 K[J]. ACTA CHIMICA SINICA,2006,64(6):501-507.
