Disulfur decafluoride is a
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the formula . It was discovered in 1934 by
Denbigh
Denbigh ( ; ) is a market town and a community (Wales), community in Denbighshire, Wales. It was the original county town of the Denbighshire (historic), historic county of Denbighshire created in 1536. Denbigh's Welsh name () translates to ...
and Whytlaw-Gray. Each
sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
atom of the molecule is
octahedral, and surrounded by five
fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...
atoms and one sulfur atom. The two sulfur atoms are connected by a single bond. In the molecule, the oxidation state of each sulfur atoms is +5, but their
valency is 6 (they are
hexavalent). is highly
toxic, with toxicity four times that of
phosgene
Phosgene is an organic chemical compound with the formula . It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. It can be thought of chemically as the double acyl chloride analog of ...
.
It is a colorless liquid with a burnt match smell similar to
sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
.
Production
Disulfur decafluoride is produced by
photolysis of :
:
Disulfur decafluoride arises by the decomposition of
sulfur hexafluoride. It is produced by the electrical decomposition of
sulfur hexafluoride ()—an essentially inert
insulator used in high voltage systems such as
transmission lines,
substations and
switchgear
In an electric power system, a switchgear is composed of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to ...
. is also made during the production of .
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 :
:S
2F
10 →
SF6 +
SF4
reacts with
to give
. It reacts with to form in the presence of ultraviolet radiation.
: + → 2
In the presence of excess
chlorine
Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...
gas, reacts to form
sulfur chloride pentafluoride ():
: + → 2
The analogous reaction with
bromine
Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...
is reversible and yields . The reversibility of this reaction can be used to synthesize from .
Ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
is oxidised by into
.
Toxicity
was considered a potential
chemical warfare pulmonary agent in
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
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
Sulfuric(IV) acid (United Kingdom spelling: sulphuric(IV) acid), also known as sulfurous (UK: sulphurous) acid and thionic acid, is the chemical compound with the chemical formula, formula .
Raman spectroscopy, Raman spectra of solutions o ...
and
hydrofluoric acid.
See also
*
Phosgene
Phosgene is an organic chemical compound with the formula . It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. It can be thought of chemically as the double acyl chloride analog of ...
*
Perfluoroisobutene
*
Bis(trifluoromethyl) disulfide
References
*
External links
*
{{Chemical agents
Pulmonary agents
Sulfur fluorides
Hypervalent molecules