Apparent molar volumes for Cs2B4O7 aqueous solution at temperatures from (283.15 to 363.15) K and 101 kPa

Densities for aqueous solutions of Cs 2 B 4 O 7 at the molalities of (0.16635–0.69694) mol·kg −1 were measured with an Anton Paar Digital vibrating-tube densimeter at temperatures from 283.15 K to 363.15 K and 101 kPa. According to experimental data, apparent molar volume ( V ϕ ), partial molar volume ( V ¯ ϕ ), and the coefficient of thermal expansion ( α ) of the Cs 2 B 4 O 7 aqueous solution were calculated, and their distributive behaviors against temperature and molality have been discussed in details. Considering the structure of Cs 2 B 4 O 7 in aqueous solution system is in the form of Cs 2 [B 4 O 5 (OH) 4 ], the Pitzer single-salt parameters ( β M , X 0 v , β M , X 1 v , β M , X 2 v and C M , X v ) for Cs 2 [B 4 O 5 (OH) 4 ] as well as temperature-dependence correlations were obtained for the first time on the basis of Pitzer ion-interaction apparent molar volume model of electrolytes. The deviations between the Pitzer single-salt parameters of Cs 2 [B 4 O 5 (OH) 4 ] fitted at each temperatures based on the experimental data and those of the calculated values corresponding to the temperature-dependence equations on Pitzer single-salt parameters are all within ±0.1, indicating that the single-salt parameters and their temperature-dependence equations obtained in this work are reliable.