Formation of oxysulfide LnO₂S₂ and oxysulfate LnO₂SO₄ phases in the thermal decomposition process of lanthanide sulfonates (Ln = La, Sm)

摘要

This study investigates two lanthanide compounds (La3+ and Sm3+) obtained in water/ethyl alcohol solutions employing the anionic surfactant diphenyl-4-amine sulfonate (DAS) as ligand. Both sulfonates were characterized through IR, TG/DTG (O₂ and N₂). The thermal treatment of both compounds at 1273 K under air leaves residues containing variable percentages of lanthanide oxysulfide/oxysulfate phases shown by synchrotron high-resolution XRD pattern including the Rietveld analysis. The phase distributions found in the residues evidence the differences in the relative stability of the precursors.