Darstellung und Eigenschaften von cyclo-Nonaschwefeloxid (S9O) und von cyclo-Dekaschwefeloxid (S10O) [1] / Preparation and Properties of cyclo-Nonasulfuroxide (S9O) and of cyclo-Decasulfuroxide (S10O) [1]

The homocyclic oxides S₉O (m.p. 33 °C, dec.) and S₁₀O (m.p. 51 °C, dec.) have been prepared by oxidation of the corresponding sulfur rings S₉ and S₁₀ , respectively, by trifluoroperoxy acetic acid (molar ratio 1:2-3) in a carbon disulfide/methylene chloride mixture. According to infrared and Raman spectra, both compounds contain an exocyclic oxygen atom. S₉O and S₁₀O decompose at 25 °C to give SO₂ and a polysulfuroxide SₙO with >10 but both can be stored at -78 °C without decomposition. The SS bond distances are discussed on the basis of the Raman spectra. In addition, the Raman spectrum of solid S₉ has been recorded for the first time. It shows that S₉ crystallizes as two allotropes (α-and β-S₉) both consisting of cyclic molecules of either C₁ or C₂ symmetry with bond distances of between 203 and 209 pm.