Disulfur decafluoride

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Disulfur decafluoride

Names
Preferred IUPAC name Disulfur decafluoride
Systematic IUPAC name Decafluoro-1λ6,2λ6-disulfane
Other names sulfur pentafluoride
Identifiers
CAS Number	5714-22-7
ChemSpider	56348 N
EC Number	227-204-4
Jmol 3D model	Interactive image
MeSH	Disulfur+decafluoride
PubChem	62586
InChI InChI=1S/F10S2/c1-11(2,3,4,5)12(6,7,8,9)10 Key: BPFZRKQDXVZTFD-UHFFFAOYSA-N
SMILES FS(F)(F)(F)(F)S(F)(F)(F)(F)F
Properties
Chemical formula	S2F10
Molar mass	254.1 g/mol
Appearance	colorless liquid
Odor	like sulfur dioxide
Density	2.08 g/cm3
Melting point	−53 °C (−63 °F; 220 K)
Boiling point	30.1 °C (86.2 °F; 303.2 K)
Solubility in water	insoluble
Vapor pressure	561 mmHg (20 °C)
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Disulfur decafluoride (S₂F₁₀) is a gas discovered in 1934 by Denbigh and Whytlaw-Gray. Each S of the S₂F₁₀ molecule is octahedral, and surrounded by 5 fluorines. S₂F₁₀ is highly toxic, with toxicity 4 times that of phosgene. It 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. 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, but is distilled out.

Production

Disulfur decafluoride is produced primarily by the decomposition of sulfur hexafluoride:

2 SF₆ → S₂F₁₀ + F₂

Properties

This compound contains sulfur in the +5 oxidation state.

At temperatures above 150 °C, S
₂F
₁₀ decomposes slowly to SF
₆ and SF
₄:

S₂F₁₀ → SF₆ + SF₄

S
₂F
₁₀ reacts with N
₂F
₄ to give SF
₅NF
₂. It reacts with SO
₂ to form SF
₅OSO
₂F in the presence of ultraviolet radiation.

In the presence of excess chlorine gas, S
₂F
₁₀ reacts to form sulfur chloride pentafluoride (SF
₅Cl):

S
₂F
₁₀ + Cl
₂ → 2 SF
₅Cl

The analogous reaction with bromine is reversible and yields SF
₅Br. The reversibility of this reaction can be used to synthesize S
₂F
₁₀ from SF
₅Br.

Ammonia is oxidised by S
₂F
₁₀ into NSF
₃.

Toxicity

Disulfur decafluoride is a colorless gas or liquid with a sulfur-dioxide-like odor. It is about 4 times as poisonous as phosgene. Its toxicity is thought to be caused by its disproportionation in the lungs into SF
₆, which is inert, and SF
₄, which reacts with moisture to form sulfurous acid and hydrofluoric acid. Disulfur decafluoride itself is not toxic due to hydrolysis products, since it is hardly hydrolysed by water and most aqueous solutions.