Thermal decomposition of cerium(III) acetate hydrate by a three-dimensional thermal analysis

The thermal decomposition of cerium(III) acetate hydrate, Ce(CH3CO2)(3).1.5H(2)O, in helium was successfully studied by the simultaneous measurement of TG-DTA and EGA by mass spectrometry (TG-DTA-MS) as well as that of X-ray diffractometry: DSC (XRD-DSC). TG-DTA-MS was useful to elucidate the complicated successive reactions accompanying the formation of intermediate products. Crystalline cefum(III) anhydrous acetate appeared at 212 degreesC and transformed to another phase at 286 degreesC. Cerium(III) anhydrous acetate decomposed in the temperature range of 300 - 700 degreesC to cefum(IV) oxide via four decomposition steps; the chemical compositions of the three decomposition intermediate products were presumed to be Ce2O(CH3CO2)(4), Ce2O2(CH3CO2)(2) and Ce2O2CO3. The endothermic dehydration and the exothermic crystallization were characterized by simultaneous XRD-DSC. It has been demonstrated that cerium(III) changed to cerium(IV) in the final step. A detailed decomposition mechanism of Ce(CH3CO2)(3).1.5H(2)O is discussed.