Electronic Properties of Antimony Chalcogenides

The electronic structure of five antimony chalcogenides, Sb${\mathrm{I}}_{3}$, ${\mathrm{Sb}}_{2}$${\mathrm{Te}}_{3}$, SbTeI, TlSb${\mathrm{S}}_{2}$, and ${\mathrm{Tl}}_{3}$Sb${\mathrm{S}}_{3}$, is investigated. Information from x-ray diffraction, M\"ossbauer spectroscopy, electrical measurements, and photoemission spectroscopy is combined with band-structure calculations to get a coherent picture of these materials. The chemical notion of the asymmetry and delocalization of the $5{s}^{2}$ antimony lone pair is given a quantitative interpretation both from the full band-structure calculation and from a simple molecular description.