The mixed-metal tris­(di­sulfide) thio­phosphate, KNb1.77Ta0.23PS10

The title compound catena-poly[potassium [tri-μ-disulfido-μ-tetra-thiophos-pha-to-di[niobate(IV)/tantalate(IV)(0.885/0.115)]]], has been obtained through the reaction of the elements with KCl. The title compound is isostructural with KNb2PS10, with the Nb sites occupied by statistically disordered Nb (88.5%) and Ta (11.5%) atoms. The structure is composed of anionic ∞ (1)[M 2PS10](-) chains along [100] (M = Nb/Ta) and K(+) ions. This chain is built up from distorted bicapped trigonal prisms [MS8] and [PS4] tetra-hedra. There are no inter-chain bonding inter-actions, except for electrostatic and van der Waals forces. The S2 (2-) and S(2-) anionic species and the M (4+)-M (4+) pair [M-M = 2.8939 (3) Å] are observed. The classical charge balance is represented by [K(+)][M (4+)]2[PS4 (3-)][S2 (2-)]3.