Study on the cesium Tutton compounds, Cs2M(XO4)2∙6H2O (M = Mg, Co, Zn; X = S, Se): Preparation, X-ray powder diffraction and infrared spectra

Abstract

The crystallization processes in the three-component systems Cs2SO4–MSO4–H2O (M=Mg, Co, Zn) have been studied at 25°C. It has been established that cesium Tutton compounds, Cs2M(SO4)2·6H2O (M=Mg, Co, Zn; X=S, Se), crystallize from the ternary solutions within large concentration ranges. The double salts were identified by means of X-ray powder diffraction and infrared spectroscopy. Infrared spectra of the cesium compounds are presented and discussed with respect to both the normal modes of the tetrahedral ions and the water molecules. The water librations are also discussed. The strength of the hydrogen bonds formed in the cesium salts as deduced from the frequencies of νOH is commented. The analysis of the spectra reveals that stronger hydrogen bonds are formed in the cesium selenates as compared to those in the respective sulfates due to the stronger proton acceptor ability of the selenate ions.