Volume properties of the ternary systems (LiCl + LiB5O8 + H2O) and (Li2SO4 + LiB5O8 + H2O) from 283.15 to 363.15 K and 101.325 kPa

In this study, densities of the two ternary aqueous solution systems (LiB 5 O 8  + LiCl + H 2 O) and (LiB 5 O 8  + Li 2 SO 4  + H 2 O) were measured using an accurate digital vibrating-tube densimeter from 283.15 to 363.15 K at an interval of 5 K and 101.325 kPa. B 5 O 8 - in aqueous solution was in the form of [B 5 O 6 (OH) 4 ] - . Therefore, the complex aqueous solution of LiB 5 O 8 is in the form of Li[B 5 O 6 (OH) 4 ]. Subsequently, the mean apparent molar volume ( V Φ θ $V_{\mathrm{\Phi }}^{\theta }$ ) and mixing ion-interaction parameters ( θ a , a ′ v ${\theta }_{a,a^{\prime }}^v$ and Ψ c , a , a ′ v ${\mathrm{\Psi }}_{c,a,a^{\prime }}^v$ , c  = Li + , a  = B 5 O 6 (OH) 4 - , a ′ $a^{\prime }$ = Cl - or SO 4 2- ) against temperature were obtained using the Pitzer equation for the first time. And then, the temperature-dependence equations for the Pitzer mixing ion-interaction parameters and the relevant temperature correlation coefficients of the equation a j, i.e. [ f ( a i , T ) =  a 1  +  a 2 ln( T /298.15) +  a 3 ( T  − 298.15) +  a 4 /(620 −  T ) +  a 5 /( T  − 227)] were also obtained through the least square fitting. These volumetric properties and parameterization Pitzer parameters obtained in this work could hopefully be used for the quantitatively predictive calculation of the physicochemical properties of the mixed electrolytes containing lithium, chloride, and sulfate ions at any temperature.