The oxide (0.3 g.) is dissolved in 20 ml. of hot 6N H2S04. The
solution is filtered and allowed to crystallize over cone. H2SO4 in
a vacuum desiccator. The product is filtered through fritted porcelain, washed twice with 10 ml. of water and once with 10 ml. of
ethanol, and dried in air for four hours. The product obtained from La by this procedure is La2(SO4)3 ?
9H2O and from Yb it is Yb2(S04)3 ? 11H2O. The remaining rare
earths and yttrium yield octahydrates. Cerium sulfate, Ce2(SO4)3 ? 5H2O, is prepared by heating 3 g,
of the chloride with 5 ml. of conc. H2SO4 until all the hydrogen
chloride has been removed. Then 20 ml. of water is added and the
product is allowed to crystallize in a desiccator.
