The crystal structure of bis(1,4-dithioniumdicyclo-[2,2,2]-octane) μ-oxo-bis[tetracyanooxorhenate(V)]tetrahydrate

Summary The structure of S(CH₂CH₂)₃S]₂Re₂O₃(CN)₈]·4H₂O has been determined from three-dimensional x-ray diffraction data. The blue crystals are monoclinic, space group P2₁/c, with cell dimensionsa=9.431(2),b=10.879(2),c=16.217(3)Å, =110.84(2)°,Z=2 andD _m=2.11 gcm^–3. Anisotropic refinement by least-squares methods of 2483 observed reflections converged toR=0.050.The centrosymmetric binuclear anion has a linear O=Re–O–Re=O grouping with an eclipsed configuration for the cyano ligands. Bond distances: Re–O (terminal)=1.69(1), Re–O (bridging)=1.921(1) and Re–C_av=2.12(2)Å. Each Re atom is displaced by 0.11(2)Å towards the terminal oxygen atom giving a slight square-pyramidal distortion of the octahedral environment. The ring-constrained cation has C–S_av=1.82(2)Å with averaged bond angles C–S–C=101(1) and S–C–C=113(1)°.