Synthesis of novel rare earth-Iron oxide chalcogenides with the La2Fe2O3Se2 structure

Highlights: → Two new compounds Ce2Fe2O3S2 and Pr2Fe2O3S2 of La2Fe2O3Se2 type have been prepared. → No analogs have been observed with Ni and Zn instead of Fe. → Geometrical stability factors have been suggested for the La2Fe2O3Se2 structure type. → No compound with the La2Fe2O3Se2 has yet been found to exhibit superconductivity. - Abstract: 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.