Sulfur difluoride is an inorganic compound with the chemical formula SF<sub>2</sub>. It can be generated by the reaction of sulfur dichloride and potassium fluoride or mercury(II) fluoride at low pressures:
The FâÂÂSâÂÂF bond angle is 98ð, and the length of SâÂÂF bond is 159 pm. The compound is highly unstable, dimerising to FSSF<sub>3</sub>. This unsymmetrical isomer of S<sub>2</sub>F<sub>4</sub> is proposed to arise via insertion of SF<sub>2</sub> into the SâÂÂF bond of a second molecule SF<sub>2</sub>:
It can also be formed from oxygen difluoride and hydrogen sulfide: