Redetermination of AgNb(2)PS(10) revealing a silver deficiency.

In comparison with a previous crystallographic study [Goh et al. (2002 ▶). J. Solid State Chem.168, 119-125] of the title compound, silver diniobium tris-(disulfide) tetra-thio-phosphate(V), that reports a full occupation of the silver position and isotropic displacement parameters for the atoms, the current redetermination reveals a silver deficiency with a site-occupation factor of 0.88 (1) and reports all atoms with anisotropic displacement parameters. The structure of Ag(0.88)Nb(2)PS(10) is composed of (∞) (1)[Nb(2)PS(10)] chains, which are built up from pairs of distorted bicapped trigonal-prismatic [NbS(8)] polyhedra forming [Nb(2)S(12)] dimers and of tetra-hedral [PS(4)] groups. These chains are connected via the statistically disordered Ag(+) ions, forming double layers. Adjacent layers are stacked solely through van der Waals forces into a three-dimensional structure. Short and long Nb-Nb distances [2.880 (1) and 3.770 (2) Å, respectively] alternate along the chain and S(2) (2-) and S(2-) anionic species are observed.