Crystal growth and thermal properties of the Tutton salt Cs2Fe(SO4)2·6H2O single crystal

Abstract

Thermal properties and phase transitions of the Tutton salt Cs2Fe(SO4)2·6H2O were investigated using thermogravimetric analysis, differential scanning calorimetry, and nuclear magnetic resonance (NMR). The first occurrence of mass loss is at approximately 321 K (=Td) and is interpreted as being the onset of partial thermal decomposition. Phase transitions were observed at 356 K (=TC1) and 450 K (=TC2). The temperature dependence of the NMR spectrum and spin–lattice relaxation time T1 for the 133Cs nuclei abruptly changes near TC1. These changes are associated with changes in the geometry of the water and five SO4 oxygens around the Cs ions.