Compounds containing CSF4 and CS+F4

The preparations of CH₂SF₄ and CH₃CHSF₄ are presented and the structures are discussed. Addition reactions of polar species give a wide range of new compounds, like Hg(CH₂SF₅)₂, F₄AsCH₂SF₅, cisBrSF₄CH₃, cisF₅SeOSF₄CH₂Br, a.o. While CH₂SF₄ decomposes at room temperature slowly to CH₂CH₂ and SF₄, at high temperatures HF and CSF₂ are formed. CH₃CHSF₄ gives mainly CH₃CHF₂ at room temperature. The “saturated” compounds CH₃SF₅ and C₂H₅SF₅ have been prepared. They react with SbF₅ in SO₂ at low temperatures to form the cations CH₃SF₄⁺ and C₂H₅SF₄⁺. The CH₃SF₄⁺ ion has been investigated in detail by nmr methods at low temperatures. It decomposes to CH₃ and SF₄, which react further in the SO₂/SbF₅ system to CH₃OSO⁺ and SF₃⁺.