A New Quasi-One-Dimensional Ternary Chalcogenide: Synthesis, Crystal Structure, and Electronic Structure of Nb₁₊<i>_x</i>V₁_-<i>_x</i>S₅ (<i>x</i> = 0.18)

The new low-dimensional ternary chalcogenide, Nb1+xV1-xS5 (x = 0.18), has been prepared and characterized. This compound crystallizes in the monoclinic space group, h-P21/m with two formula units in a cell with dimensions a = 9.881(4) Å, b = 3.329(1) Å, c = 8.775(3) Å, and β = 114.82(3)°. The layer is composed of two unique chains of face-sharing Nb-centered bicapped trigonal prisms and edge-sharing M-centered octahedra (M = Nb or V). The electronic structures of the monomeric basic building units, NbS8 and VS6, and hypothetical and real one-, two-, and three-dimensional structures making up the compound are examined to understand the nature of inter- and intrachain interactions and orbital overlapping among metals and sulfur atoms. The electronic structure of Nb1+xV1-xS5 is essentially given by superimposing those of the individual chains. V d orbitals are found to be crucial for the one-dimensional metallic conductivity along the chain axis.