Dark-red square plates of the previously reported compounds "(UO) 2LnS3" (Ln = Yb, Y) have been synthesized by solid-state reactions of UOS and YbS or Y2S3 with Sb 2S3 as a flux at 1273 K. The structure of these isotypic compounds was reinvestigated by single-crystal X-ray diffraction methods and an inductively coupled plasma experiment. The actual formula of "(UO) 2LnS3" (Ln = Yb, Y) is (U0.5Ln 0.5O)2LnS3, that is, ULn2O 2S3, which can be charge-balanced with U4+ and Ln3+. The layered structure comprises (U/Ln)O4S 4 square antiprisms alternating with LnS6 octahedra. U and Ln1 atoms disorder on the eight-coordinate metal position, but Ln2 atoms occupy the six-coordinate metal position exclusively. UYb2O 2S3 is a modified Curie - Weiss paramagnet between 293 and 32 K, below which part of the paramagnetic moments go through a possible ferromagnetic transition. The band gaps of ULn2O2S 3 (Ln = Yb, Y) are around 2 eV.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry