Neue Synthesewege für Thiohalogeno- und Cyclothioarsenate(III). Kristallstrukturen von PPh4[As2SBr6] · CH3CN und PPh4[SAsS5]

Novel Routes to the Synthesis of Thiohalogeno- and Cyclothioarsenates(III). Crystal Structures of PPh₄[As₂SBr₆] · CH₃CN and PPh₄[SAsS₅] By reactions of (PPh₄)₂[As₂Cl₈] and (PPh₄)₂[As₂Br₈] with Na₂S₄ in acetonitrile (PPh₄)₂[As₂SCl₆] · CH₃CN and (PPh₄)₂[As₂SBr₆] · CH₃CN were obtained, respectively. Using K₂S₅, PPh₄[As₂SCl₅] and PPh₄[SAsS₅] were the products. The latter can also be obtained from PPh₄[As₂SCl₅] and Na₂S₄, while PPh₄[As₃S₃Br₄] is formed from PPh₄[As₂SBr₅] with K₂S₅. Two X-ray crystal structure determinations were performed. PPh₄[As₂SBr₆] · CH₃CN: triclinic, P1 , Z = 2, a = 1200.4(7), b = 1507.3(6), c = 1594.4(8) pm, α = 81.59(2), β = 78.22(3), γ = 80.58(2)°, R = 0.096 for 2298 observed reflexions. The structure contains [As₂SBr₆]^2? -ions in which the two Sb atoms are joined via one S and two Br atoms. PPh₄[SAsS₅]: triclinic, P1 , Z = 2, a = 1133.9(4), b = 1142.5(4), c = 1186.9(5) pm, α = 102.77(4), β = 107.74(3), γ = 106.65(3)°, R = 0.043 für 2677 reflexions. In the [SAsS₅]^? -ion an AsS₅ ring in the chair conformation is present.