engleski

Synthesis, identification and thermal decomposition of double sulphates of some lanthanides and Y with ethanolammonium cation

On evaporation at room temperature of an aqueous mixture of Ln(III) sulphate and ethanol ammonium sulphate in a molar ratio higher than 1:12, in the presence of sulphuric acid, double sulphates of Sm, Eu, Ho, Tm, Yb and Y with a waxy feel were obtained. The stoichiometry of the obtained compounds was determined by means of elemental and TG analysis. On the basis of x-ray powder diffraction patterns it was concluded that an isostructural group with a general formula Ln2(HOCH2CH2NH3)8(SO4)7.8H2O was obtained. The above compounds have a stoichiometry and a crystal structure different from those of the double sulphates of La, Ce, Pr and Nd with the same monovalent cation, as presented earlier. The thermal decomposition of the investigated compounds in the temperature range from ambient temperature up to 1173 K occured in a similar way, mainly in three not well-differentiated steps. Lanthanide oxysulphates were obtained as final product.

double sulphates ; ethanolammonium ; lanthanides ; thermal decomposition

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