121Sb Mössbauer and X-ray Photoelectron Spectroscopy Studies of the Electronic Structure of Some Antimony Misfit Layer Compounds

The chemical environment of Sb atoms in misfit layer sulfides (SbS)pTS2 (T = Nb, Ti and Ta) was examined by using 121Sb Mossbauer spectroscopy (MS) and X-ray photoelectron spectroscopy (XPS). 121Sb Mossbauer spectra exhibited an asymmetric profile that can be interpreted by assuming two different coordination numbers for trivalent Sb ions. However, these data do not give evidence for the presence of a significant Sb atom fraction of valence similar to metallic antimony as reported by X-ray single-crystal structure calculations. Sb 3d peak profiles were found to be highly symmetric and to suggest the presence of a single electronic state for Sb atoms within the SbS lattice. Although the binding energy of Sb 3d electrons in Sb-containing misfit layer sulfides was found to coincide with that in Sb2S3, the Wagner−Auger parameter values are intermediate between those reported for Sb2S3 and metallic Sb.