Acta Cryst. (2007). E63, m2386-m2387  [ doi:10.1107/S1600536807039293 ]

catena-Poly[[tetrakis(hexamethylphosphoramide-O)bis(nitrato-²O,O')europium(III)] [silver(I)-di--sulfido-tungstate(VI)(Ag-W)-di--sulfido]]

J. Zhang, J. Qian, Y. Cao and C. Zhang

Abstract: Hexamethylphosphoramide (hmp), tetrathiotungstate, silver sulfide and europium nitrate were self-assembled to form a one-dimensional anionic [AgWS₄]^- chain generated by the 2₁ symmetry operation, {[Eu(NO₃)₂(C₆H₁₈N₃OP)₄][WAgS₄]}_n. The central Eu in the cation is coordinated by eight O atoms from two nitrate and four hmp ligands, which gives rise to a distorted square-antiprismatic structure like those in the isostructural Yb and Y compounds. Parts of the dimethylamine groups from the hmp ligands have large librations. Together with the two nitrate ligands, the cation in the title compound is monovalent, which leads to the anionic chain having a monovalent repeat unit. This contrasts with solvent-coordinated rare-earth cations, which are trivalent and induce trivalent repeat units in the anionic chains. The polymeric anionic chain in the title compound, with W-Ag-W and Ag-W-Ag angles of 162.93 (2) and 154.250 (9)°, respectively, presents a distorted linear configuration, unlike those in {(-MePyH)[WS₄Ag]}_n and {[NH₃C(CH₂OH)₃][WS₄Ag](2DMF)}_n (DMF is dimethylformamide), showing an ideal linear chain and a nearly linear chain, with W-Ag-W and Ag-W-Ag angles of 176.4 (5) and 176.4 (3)°, respectively. This fact suggests that cations with bigger bulk lead to more distorted anionic chains. At the same time, the anionic skeleton in the title compound is the same as those in {[M(hmp)₄(NO₃)₂][WS₄Ag]}_n (M = Yb, Y), implying that different rare-earth cations with the same coordination environments have the same influence on the arrangement of their anionic skeletons.

Online 17 August 2007

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