Volumetric properties and the ion-interaction parameters of the binary system (CsB5O8 + H2O) at temperatures from (283.15 to 363.15) K and 101 kPa

This paper reports the densities of CsB5O8 (aq) in the range of salt concentrations from 0.02526 to 0.08148 mol·kg−1, which were determined by an accurate Anton Paar Digital vibrating-tube densimeter at 5 K intervals from 283.15 to 363.15 K and 101 kPa. The apparent molar volume (Vϕ), the coefficient of thermal expansion (α), apparent molar expansibility of the solute (ϕE) were calculated and variations of these properties against temperature and concentration were revealed minutely. According to Pitzer ion-interaction apparent molar volume model of aqueous electrolyte system, the Pitzer single salt parameters i.e. FMX ( β M X 0 v , β M X 1 v and C M X v , M = Cs+, X = [B5O6(OH)4]-), the temperature-dependence equation [FMX (i, p, T) = a1 + a2ln(T/298.15) + a3(T-298.15) + a4/(620-T) + a5(T-227), i = β M X 0 v , β M X 1 v and C M X v ] as well as their coefficients ai (i = 1 to 5) in the binary system were obtained, which is not reported in the literature. The fitted results of single salt parameters β M X 0 v , β M X 1 v and C M X v were in good agreement with the experiment values, indicating that the single salt parameters and temperature relational coefficients for Cs[B5O6(OH)4] obtained in this work are reliable.