五硼酸铷溶液的物化性质及物种分布

Physicochemical Properties and Species Distribution of Aqueous Rubidium Pentaborate solutions

碳酸铷、硼酸化学计量比混合,蒸发溶液,直至五硼酸铷RbB_5O_8·4H_2O晶体析出。经粉末X射线衍射、拉曼光谱、热重/微商热重/差示扫描量热(TG/DTG/DSC)、原子吸收光谱等实验方法,确定其化学组成及结构,298.15、333.15K时测量溶液的物理化学性质(密度、电导、pH),并与经验方程进行拟合,研究五硼酸铷溶液的物化性质随浓度、温度的变化规律。根据文献报道的平衡常数、实验测量的p H数据,采用牛顿迭代法进一步探讨了五硼酸铷溶液中主要存在的硼酸根离子物种分布规律。

Hydrated rubidium pentaborate was precipitated via evaporating solution of rubidium carbonate and boric acid in stoichiometric proportions. The chemical composition and structural information about the synthesized compound were achieved using different methods of powder X-ray diffraction, Raman spec- troscopy,TG/DTG/DSC and atomic absorption spectroscopy. Physicochemical properties including densi- ty, electrical conductivity and pH of aqueous rubidium pentaborate solutions, have been accurately deter- mined at temperature of 298. 15 and 333.15 K, respectively. Furthermore, the empirical equations were used to fitting with these experimental data. On the basis of these, the change rules of the physicochemical properties with temperature and concentration were investigated. According to the equilibrium constants reported in literature and experimental pH data, the polyborate anion distribntion were given by Newton it- eration,besides, the speciation among deferent anions in solution were speculated.