Synthesis of novel rare earth - iron oxide chalcogenides with the   La2Fe2O3Se2 structure
  Our searches for new oxide chalcogenides of rare earths and Fe, Co, Ni, and Zn resulted in preparation of two new compounds Ce2Fe2O3S2 and Pr2Fe2O3S2 which are isostructural to La2Fe2O3Se2 and Sm2Ti2O3Sb2. Crystal structures of the new compounds Ce2Fe2O3S2 and Pr2Fe2O3S2 were determined from powder X-ray diffraction data. Magnetic measurements were performed for Ce2Fe2O3S2 and revealed behavior very similar to that of isostructural oxide chalcogenides of iron and pnictides of titanium. In particular, no superconductivity was observed down to 4 K. Crystal chemical factors determining the stability of the La2Fe2O3Se2 structure type are discussed. 
D.O. Charkin, V.A. Plotnikov, A.V. Sadakov, O.E. Omel'yanovskii, S.M.   Kazakov
cond-mat.mtrl-sci