Thiochloroarsenate(III): Darstellung,Schwingungsspektren und Kristallstrukturen von PPh4[As2SCl5] und (PPh4)2[As2SCl6] · C2H4Cl2

Thiochloroarsenates (III): Preparation, Vibrational Spectra, and Crystal Structures of PPh₄As₂SCl₅] and (PPh₄)₂As₂SCl₆] · C₂H₄Cl₂ PPh₄As₂SCl₅] can be obtained from As₂S₃ + PPh₄Cl with HCl in CH₂Cl₂ or 1,2-C₂H₄Cl₂. It reacts with a second mole of PPh₄Cl to yield (PPh₄)₂As₂SCl₆]. The latter also is formed by the reaction of As₂S₅ + 2 PPh₄Cl with HCl, a second product being (PPh₄)₂As₂Cl₈]. The i.r. and Raman spectra of the title compounds are reported. Their crystal structures were determined by X-ray diffraction. Crystal data: PPh₄As₂SCl₅], monoclinic, space group P2₁/n, a = 1175.8, b = 1508.0, c = 1593.4 pm, β = 96.22°, Z = 4; (PPh₄)₂As₂SCl₆] · C₂H₄Cl₂, triclinic, P1, a = 1166.3, b = 1188.2, c = 2044.6 pm, α = 95.47, β = 97.53, γ = 111.05°, Z = 2. Including the lone electron pairs, the coordination of the As atoms in the As₂SCl₅]^? ion is distorted trigonal-bipyramidal with the S, one Cl atom, and an electron pair in equatorial positions; the two bipyramids around the two As atoms share a common edge. The As atoms in the As₂SCl₆]^2? ion have a distorted octahedral coordination, the two octahedra share a common face; the lone electron pairs are in the trans positions to the S atom.