A new double salt, RbBr NiBr 6H O, crystallizing as the only possible double salt at 2 2
Ts298.15 K from aqueous rubidiumαnickel bromide solutions was predicted using Pauling Ε½ rules and the ''hard'' and ''soft'' Lewis acids and bases concept. The system m RbBr q 1 .Ε½ . m NiBr aq , where m denotes molality, was thermodynamically simulated by the Pitzer 2 2 method under the assumption that the solubility diagram consists only of three branches, . . . namely RbBr, RbBr NiBr 6H O, and NiBr 6H O. The theoretical result was 2 2 2 2 experimentally proved at T s 298.15 K by the physicochemical analysis method, and the . . formation of the new double salt RbBr NiBr 6H O was established. The double salt 2 2 Ε½ . crystallizes in a monoclinic crystal system, space group C2rc, a s 0.9572 2 nm, b s Ε½ . Ε½ . Ε½ . Ε½ . 3 0.9759 2 nm, c s 1.3666 2 nm, β€ s 90.12 2 Π, V s 1.2766 4 nm , unit cell Z s 4, unit cell density D s 2.560 grcm y3 . The binary and ternary ion interaction parameters were x calculated and the solubility isotherm was plotted. The standard molar Gibbs energy of the T . . synthesis reaction β¬ G of the double salt RbBr NiBr 6H O from the corresponding r m 2 2 . simple salts RbBr and NiBr 6H O, as well as the standard molar Gibbs energy of formation 2 2
β¬G T of the simple and double salts were calculated.