PDGES3 - A NOVEL ONE-DIMENSIONAL METATHIOGERMANATE

The novel compound PdGeS3 has been synthesized by direct reaction of t he elements at 600 degrees C. Single crystals of the fibrous material were grown in a molten flux of NaSCN. The crystal structure was determ ined by single-crystal X-ray diffraction techniques. PdGeS3 crystalliz es in the monoclinic space group C2/m (a = 14.217(6), b = 3.453(2), c = 9.079(6) Angstrom, beta = 106.58(4)degrees, Z = 4). The structure is characterized by one-dimensional (1)(infinity)[(PdGeS3)(2)] double st rands that run along the b axis. These are built up by two opposite ch ains of corner-sharing GeS4 tetrahedra, representing {uB, 1(infinity)( 1)}[(GeS3)-Ge-1](2-) einer single chains. The palladium atoms connecti ng these chains reside in distorted square-planar environments surroun ded by four sulfur atoms. High anisotropy of chemical bonding emerged because interactions between the strands consisist of van der Waals fo rces exclusively. The juxtaposition of the double chains is similar to a two-dimensional hexagonal close-packed arrangement. The electronic structure and bonding is analyzed in real space by means of the electr on localization function (ELF) resulting from self-consistent LMTO ban d structure calculations. Peculiarities in the atomic arrangement of t he strands are explained by the spatial requirements of the lone pairs of electrons on sulfur and their interactions with the palladium atom s. The mutual dependencies of the bonding within and between the chain s are discussed by using a two-dimensional ELF map.