Abstract: The solubilities of rubidium bromide and cesium bromide in water, water+ methanol, and water+ethanol were measured by using accurate analytical method at different temperatures. And refractive indices were determined for the two ternary systems in saturated solution with varied salt concentrations as well. In all cases, the presence of either methanol or ethanol significantly reduced the solubilities of rubidium bromide and cesium bromide in aqueous solution, but the refractive indices reduced with the increasing mass fraction of either methanol or ethanol. The solubilities of the saturated solutions were fitted via polynomial equations as a function of the mass fraction of methanol or ethanol, and the salting-out ratios of RbBr and CsBr by methanol and ethanol were also obtained.

Key words: Rubidiumbromide, Cesiumbromide, Methanol, Ethanol, Solubility, Refractive index