Syntheses of Rubidium- and Cesium Triiodides in Supercritical Carbon Dioxide

Abstract

By knowing the physical-chemical properties of supercritical CO₂ and its extended use as an attractive continuous phase for different applications, we employed in this study supercritical CO₂ as a reaction medium for syntheses between inorganic species. In this course of investigation, aiming to obtain the ternary compounds M₂SnI₆ (M = Rb, Cs) in supercritical CO₂ using a self made lab-scale system at 200 ºC, 220 bar for one week, instead of the desired product, we obtained the triiodides of rubidium (RbI₃) and cesium (CsI₃). Small amounts of water, introduced as impurity played a determinant role in the syntheses, meanwhile, the presence of tin(IV) iodide and supercritical CO₂ were crucial factors for the occurrence of triiodides.