Disulfur difluoride

Disulfur difluoride is an inorganic compound with the chemical formula S2F2. It is a halide of sulfur.

Structure
Disulfur difluoride has a chain structure F\sS\sS\sF. The angle between the F^{a}\sS\sS and S\sS\sF^{b} planes is 87.9°, while the angles of F^{a}\sS\sS and S\sS\sF^{b} are equivalent, and are equal to 108.3°. Both S\sF bonds are equivalent and their length is 163.5 pm, while the length of the S\sS bond is 189 pm. This structure is referred to as gauche, and is similar to H2O2.

There is a branched isomer of disulfur difluoride, thiothionyl fluoride, with the structure S\dSF2.

Synthesis
Silver(II) fluoride can fluorinate sulfur in a strictly dry container at 125 C, and the reaction produces FS\sSF:


 * S8 + 8 AgF2 → 4 S2F2 + 8 AgF

Reactions
Disulfur difluoride undergoes intramolecular rearrangement in the presence of fluorides of alkali metals, yielding the isomer S=SF2:


 * FS\sSF → S\dSF2


 * Decomposing to sulfur tetrafluoride and sulfur when heated to 180 °C:
 * 2 S2F2 → SF4 + 3 S


 * Hydrolysis:
 * 2 S2F2 + 2 H2O → SO2 + 3 S + 4 HF


 * Reacting with sulfuric acid at 80 °C:
 * S2F2 + 3 H2SO4 → 5 SO2 + 2 HF + 2 H2O


 * Reacting with sodium hydroxide:
 * 2 S2F2 + 6 NaOH → Na2SO3 + 3 S + 4 NaF + 3 H2O


 * Reacting with oxygen at high pressure, using nitrogen dioxide as a catalyst:
 * 2 S2F2 + 5 O2 → SOF4 + 3 SO3