| Popis: |
On evaporation at room temperature of an aqueous reaction mixture of Ln(III) sulfate and ethanolammonium sulfate in a molar ratio higher than 1∶16, crystal products with a waxy feel were obtained. They were identified by means of the X-ray powder diffraction patterns and it was concluded that they are isostructural. The results of elemental analysis and the mass losses by TG analysis indicated the formation of double sulfates with general formula: (HOCH2CH2NH3)4Ln2(SO4)5·4.5H2O (Ln=La, Ce, Pr or Nd) Their thermal decompositions in static atmosphere in the temperature range from ambient up to 1173 K took place in a similar way, and mainly Ln2O2SO4 was obtained as final product. The exception was the Ce compound, which decomposed to CeO2. The double sulfates decomposed in many not well-differentiated steps. From the mass losses occurring during thermal decomposition, the mode of thermal decomposition was presumed. The X-ray powder diffraction patterns of Ln2O2SO4 (Ln=La, Pr and Nd) show that they are also isostructural. |
