High pressure synthesis of ternary thioborates.

Abstract

So far we have synthesized CaB₂S₄-I and CaB₂S₄-II, and have solved the crystal structure of CaB₂S₄-II. In this work, single phase of CaB₂S₄-I was obtained and its X-ray diffraction pattern can be indexed on a tetragonal unit cell (l4₁/a, a=13.75, c=13.20Å). The structural model of CaB₂S₄-I was deduced by the direct method using the program EXP0 and refined by the Rietveld method using the program RIETAN2000. Final R values were converged to be R_I=3.78 %, R_F=2.53 %, and S=1.36. It was revealed that CaB₂S₄-I is made up from isolated [B₁₀S₂₀]^10-- macrotetrahedral units.