SYNTHESIS AND CHARACTERIZATION OF 2 NEW QUATERNARY CHALCOGENIDES, CAYBINQ4 (Q = S AND SE), WITH AN OLIVINE-TYPE STRUCTURE

Two new quaternary chalcogenide compounds, CaYbInQ4 (Q = 8 and Se), were synthesized using a eutectic halide flux. The preliminary results from infrared spectroscopy experiments, using both DRIFTS and single-crystal transmittance methods, show no strong absorption bands in an extended infrared region (2-25 mum). These phases were structurally characterized by a single-crystal X-ray diffraction method. They crystallize in an orthorhombic crystal system with space group Pnma (No 62) and Z = 4. The cell dimensions are a = 13.639 (2) angstrom, b = 7.926 (2) angstrom, c = 6.503 (2) angstrom, V = 703.1 (5) angstrom3 for the sulfide compound and a = 14.282 (3) angstrom, b = 8.247 (2) angstrom, c = 6.776 (1) angstrom, V = 798.1 (5) angstrom3 for the selenide compound. The structure solutions of these chalcogenide analogues show that they adopt an olivine-type structure (Mg2SiO4). Structure refinements and chemical analysis suggest nonstoichiometry, which can possibly be attributed to cation mixing in an indium rich phase. The synthesis, structure characterization, and spectroscopy of the title compounds are discussed in this paper.