1,1,1,2-tetrafluorodisulfane, also known as 1,2-difluorodisulfane 1,1-difluoride or just difluorodisulfanedifluoride (FSSF3) is an unstable molecular compound of fluorine and sulfur.

[3] Feq is 90° from Ftrans, and 84° from Fcis, and the torsion compared to Ftop is about 95°.

[3] As a gas, at ambient and totally clean conditions, FSSF3 decomposes with a half life of about 10 hours.

[8] Separation of the sulfur fluorides can be achieved by low temperature distillation.

[9] SF3SF is also made in small amounts by reacting sulfur with silver fluoride, or photolysis of disulfur difluoride and SSF2.

[3] The nuclear magnetic resonance spectrum of FSSF3 shows four bands, each of eight lines at -53.2, -5.7, 26.3 and 204.1 ppm.

[8] The related compound FSSSF3 has a similar structure, but with an extra sulfur atom in the chain.