STRUCTURAL RELATIONSHIP BETWEEN THE ORTHORHOMBIC, MONOCLINIC AND TRICLINIC MISFIT LAYER COMPOUNDS (MS)NTS2 (M = SN, PB, RARE-EARTH-METALS, T = TI, V, CR, NB, TA - 1.13-LESS-THAN-N-LESS-THAN-1.21)

Unit cell dimensions of the two structural units MS and TS2 are reported for the monoclinic misfit layer compounds (PbS)1.18TiS2 and (PbS)1.13VS2, and for the triclinic compound (SnS)1.20TiS2. They are compared with the unit cells of the orthorhombic misfit layer compounds and with triclinic (LaS)1.2CrS2. In all cases it is found that the reciprocal lattices of the substructures MS and TS2 have a common (b*,c*)-plane. A building principle is formulated, which states that a stabilizing interlayer interaction is obtained if the M atoms of the MS double layers fall in the groves formed by sulfur atoms of TS2 sandwiches. Using this principle, the occurence of orthorhombic, monoclinic and triclinic symmetries is explained. © 1990.