Disulfur decafluoride
Disulfur decafluoride (SF) is a chemical compound discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the SF molecule is octahedral, and surrounded by five fluorine atoms. SF 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 SFBr: Disulfur decafluoride arises by the decomposition of sulfur hexafluoride. It is produced by the electrical decomposition of sulfur hexafluoride (SF)—an essentially inert insulator used in high voltage systems such as transmission lines, substations and  switchgear. SF is also made during the production of SF. 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) to and : In the presence of excess chlorine gas, reacts to form sulfur chloride pentafluoride (): 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 . 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 SO-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.