The reflectivity of powdered lanthanide oxysulfides

By a method described in [2, 3] we synthesized samarium sesquioxide and oxysulfide with the stoichio~tric composition SmaO=S. The results of chemical analysis of the synthesized compounds are presented in Table I. It was established that the diffractograms of nonstoichiometric lanthanide oxysulfides differ from the diffractograms of the corresponding compounds with stoichiometric composition but they do not contain reflexes of oxides [i, 4]. This makes it possible to regard the obtained substances as separate chemical substances.