Disulfur decafluoride

Disulfur decafluoride is a chemical compound with the formula S2F10. It was discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the S2F10 molecule is octahedral, and surrounded by five fluorine atoms and one sulfur atom. The two sulfur atoms are connected by a single bond. In the S2F10 molecule, the oxidation state of each sulfur atoms is +5, but their valency is 6 (they are hexavalent). S2F10 is highly toxic, with toxicity four times that of phosgene.

It is a colorless liquid with a burnt match smell similar to sulfur dioxide.

Production
Disulfur decafluoride is produced by photolysis of SF5Br:
 * 2 SF5Br → S2F10 + Br2

Disulfur decafluoride arises by the decomposition of sulfur hexafluoride. It is produced by the electrical decomposition of sulfur hexafluoride (SF6)—an essentially inert insulator used in high voltage systems such as transmission lines, substations and switchgear. S2F10 is also made during the production of SF6.

Properties
The S-S bond dissociation energy is 305 ± 21 kJ/mol, about 80 kJ/mol stronger than the S-S bond in diphenyldisulfide.

At temperatures above 150 °C, decomposes slowly (disproportionation) into  and :
 * S2F10 → SF6 + SF4

reacts with Tetrafluorohydrazine to give Difluoroamino sulfur pentafluoride. It reacts with to form  in the presence of ultraviolet radiation.


 * + → 2

In the presence of excess chlorine gas, reacts to form sulfur chloride pentafluoride :


 * + → 2

The analogous reaction with bromine is reversible and yields. The reversibility of this reaction can be used to synthesize from.

Ammonia is oxidised by into Thiazyl trifluoride.

Toxicity
was considered a potential chemical warfare pulmonary agent in World War II because it does not produce lacrimation or skin irritation, thus providing little warning of exposure. Disulfur decafluoride is a colorless gas or liquid with a SO2-like odor. It is about four times as poisonous as phosgene. Its toxicity is thought to be caused by its disproportionation in the lungs into, which is inert, and , which reacts with moisture to form sulfurous acid and hydrofluoric acid.