Synthesis of Sulfides with the Calcium Ferrite Structure,

摘要

Ternary sulfides with the calcium ferrite structure can be synthesized by reacting the appropriate oxides or carbonates at temperatures of 900to 1400C in an atmosphere of flowing H2S. Compounds synthesized include SrHo2S4, SrDy2S4, SrTm2S4, SrEr2S4,Eu(2+)Yb2S4, BaNd2S4, BaGd2S4and BaYb2S4. Compounds were fine grained powders,light colored,and stable in air. They were characterized by measurement of unit cell dimensions and band gap. Precision x-ray powder data are presented. Increase in oxygen activity of the gas stream leads to formation of oxysulfides. Powder data for the oxysulfides are also presented. No single crystals could be grown in spite of repeated attempts by a variety of CVD,hydrothermal and flux techniques.