Discontinuities in the mixed-crystal series of isostructural carnallite-type double salts

✍ Scribed by Christomir Christov

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 352 KB
• Volume: 27
• Category: Article
• ISSN: 0021-9614
• DOI: 10.1006/jcht.1995.0085

✦ Synopsis

The molalities b of (b1RbCl•MgCl2•6H2O+b2RbBr•MgBr2•6H2O)(aq) have been investigated at the temperature T=323.15 K and formation of a discontinuous series of mixed crystals has been established. On the basis of the present and earlier experimental results, it has been established that the formation of a continuous mixed-crystal series of isostructural carnallite-type double salts depends on close values of the unit-cell parameters. The parameter Dd, accounting for the differences in the unit-cell volumes of the participating double salts and their mole fractions in the mixed crystals, is proposed as a quantitative criterion. It has been experimentally proved that the continuous mixed-crystal series is interrupted when Dde2.5•10 -2 . In systems where continuous mixed-crystal series are formed, the distribution coefficients correspond to the theoretical values calculated according to the equation of isomorphic co-crystallization. On the basis of this condition, the solubilities in (b1RbCl•MgCl2•6H2O+b2CsCl•MgCl2•6H2O)(aq) at T=323.15 K are determined theoretically.