Oxysulfate/oxysulfide of Tb3+ obtained by thermal decomposition of terbium sulfate hydrates under different atmospheres

摘要

The terbium oxysulfate/oxysulfide Tb2O2SO4/Tb2O2S were prepared from two different precursors: Tb(DAS)(3)center dot 2H(2)O and Tb-2(SO4)(3)center dot 8H(2)O, utilizing two different atmospheres of thermal decomposition. The reaction of Tb4O7 with aqueous solution of H2SO4 (2 mol L-1) produces Tb-2(SO4)(3)center dot 8H(2)O; after isolation and purification, it was reacted with Ba(DAS)(2)center dot H2O in aqueous solution to produce Tb-2(DAS)(3)center dot 2H(2)O precursor. Both of the terbium sulfonate Tb(DAS)(3)center dot 2H(2)O and terbium sulfate Tb-2(SO4)(3)center dot 8H(2)O precursors were analyzed in two different atmospheres of thermal treatment; in air atmosphere, terbium oxysulfate Tb2O2SO4 was obtained as the end product; and in reducing (CO) atmosphere, terbium oxysulfide Tb2O2S one was obtained. Thus, it was observed that the change of precursor can result in obtaining different size of particles. Moreover, it was also observed that the terbium oxysulfate Tb2O2SO4 obtained from sulfonate precursor at 1223 K, while from sulfate one at 1323 K. Similarly, the terbium oxysulfide Tb2O2S obtained from both sulfonate and sulfate precursors did not show significant difference, at 1013 K from sulfonate and 1033 K from sulfate precursor.