The practical use of rare-earth oxysulfides is limited by the difficulties associated with their synthesis.

Scientists of the Department of Inorganic and Physical Chemistry at TomSU proposed a synthesis method - the use of rare-earth elements as a precursor. To obtain the desired compound, the authors prepare an aqueous solution of nitrates, which contains all the necessary components, and then, by coprecipitation, transfer into a solid solution of sulfates of rare-earth elements. After chemical homogenization, during which lanthanide ions — cerium, europium, dysprosium, and erbium — are introduced into the reaction mixture, the resulting compounds are reduced in a hydrogen atmosphere and sulfidized in an H₂S atmosphere.

The authors report that the crystal structure of the synthesized compounds has trigonal symmetry.

The work has been published in the Journal of Solid State Chemistry.