Density, electrical conductivity, viscosity and acidity of aqueous NaBO2, Na2B4O7 and NaB5O8 solutions were preciously measured as functions of concentration from dilute to super-saturation at 298.15 and 323.15 K. The results are in reasonable agreement with literature data where comparisons are possible. Semi-empirical equations for those properties vs concentration were also suggested. Coupling with Raman spectra of some concentrated samples, main species and possible equilibria were listed by elaborate deduction. In aqueous sodium borate solutions, at least five polyborate species i.e. B(OH)3, B(OH)4-, B3O3(OH)4-, B4O5(OH)42- and B5O6(OH)4- exist, and their distribution and relevant mechanism were also suggested


ZHOU YONGQUAN, FANG CHUNHUI, FANG YAN, ZHU FAYAN