Synthesis and Crystal Structure Refinement of Sb2Se3-xSx Solid Solutions by Rietveld Analysis of X-Ray Powder Diffraction Data

Bulk materials of Sb2Se3-xSx solid solutions (x = 0, 1, 2 and 3) have been synthesized by fusion of the constituent elements in the stoichiometric ratios in vacuum-sealed silica tubes. The materials compositions were confirmed by using energy dispersive analysis of X-rays (EDAX). X-ray powder diffraction measurements were performed for all the prepared samples at 300 K. The analysis of X-ray data has indicated that all the prepared materials are polycrystalline of single-phase and belonging to the orthorhombic system with space group Pbnm (62). The crystal structural parameters were refined by Rietveld method using the FullProf program. The influence of the S-content in the ternary compounds on the structural properties was discussed. It was verified that the investigated compositions are formed of infinite puckered chains of stoichiometric composition indefinitely extended in the plane parallel to the c-axis. These larger chains are, in turn, bonded into sheets roughly perpendicular to the b-axis through sets of Sb-Se/S bonds, weaker than that within the chain. Finally, the sheets are held together to make the crystalline solid.