Thermal decomposition of the hydrated basic carbonates of lanthanides and yttrium

Thermogravimetry, differential thermal analysis, differential scanning calorimetry, IR absorption spectroscopy, X-ray diffraction, and other methods of analysis have been used in the characterization and study of the thermal decomposition of the basic carbonate hydrates of lanthanides and yttrium. These compounds were obtained by precipitation from homogeneous solutions via the hydrolysis of urea, without the addition of an auxiliary anion. The results show that the TG and DTA curves are characteristic for each compound. The results also permit suggestions concerning the compositions and mechanisms of thermal decomposition of these compounds. © 1989.

Studies on double selenates. XI. Thermal decomposition of lanthanides of the ceric group and lithium double selenates

A previous communication [1] described the preparation of the double selenates of lanthanum and the alkali metals; the La-Li compound has the formula La2(SeO4)3 · Li2SeO4 · 8H2O. Subsequent reports [2-4] have shown that it was not possible to prepare the Ce-Li, Pr-Li, Nd-Li and Sm-Li double selenates, using the same method [1]. It was possible to isolate the double selenates of all the cerie group lanthanides and lithium not previously described and, also, a La-Li double selenate having a different stoichiometry, using a modified preparation technique. © 1990.