Separation of hydration isomers of51CrCl3·6H2O by thin-layer chromatography and its application to the investigation of isomeric transitions occurring in the titration of these isomers with a base

Abstract

A thin-layer chromatographic method was elaborated for the separation of hydration isomers of51CrCl3·6H2O. The layer consists of Dowex 50WX4 and microcrystalline cellulose. As developing solvent the aqueous solution of NaClO4 and NaCl is used. The precision of the method for the determination of the amounts of the dark-and light-green isomers is ±2 abs %., and for that of the violet isomer ±0.5 abs %. The method was used in the study of changes occurring in the aqueous solutions of pure isomers in the course of titration with NaOH or in back titration with HCl. From the results obtained it follows that the transitions of hydration isomers of CrCl3·6H2O from dark- and light-green to the violet form or the basic forms of chromium(III) chloride or chromium(III) hydroxide is irreversible in aqueous solutions.