A TEM and XRD study of (BiS)1+δ(Nb1+εS2)n misfit layer structures

Abstract

Monolayer and bilayer lamellar misfit layered chalcogenides within the BiS-NbS2 system have been synthesized and studied via TEM and XRD. Both BiS and NbS2 parent substructures are shown to have very close to orthorhombic symmetry in the former case, but definite monoclinic symmetry in the latter. Stacking disorder and its effect upon electron diffraction patterns is investigated via higher order Laue zone (HOLZ) diffraction. In addition to the usual set of reflections for such systems, an additional set of weak, somewhat diffuse satellite reflections (not previously reported before for any other misfit layered chalcogenide) have been observed. Bilayer tubular crystals have also been studied by XRD. A close relationship with the corresponding lamellar bilayer phase is established, and some unusual features of its reciprocal lattice are pointed out. Show more