Rubidium bromide, RbBr

The methods for the formation of the Rubidium bromide, RbBr, are similar to those employed for the production of rubidium chloride. The salt is colourless, crystallizes in cubes, and is stated to melt at 681° C. and 683° C., and to boil at 1350° C. The vapour- pressure in atmospheres is given by the expression

log p = -36980/4.57T+4.964.

Its density is given as 2.780, and also 3.210 at 23° C. Bromine is evolved at the melting-point, and is also displaced by the action of iodine. It dissolves in water much more freely than potassium bromide, the solubility at 16° C. being 105 grams in 100 grams of water. The heat of solution is -5.96 Cal. It forms polyhalides, such as RbBr₃ and RbBr₂I.