Sulfur dichloride is the
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
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
. This cherry-red liquid is the simplest sulfur chloride and one of the most common, and it is used as a precursor to
organosulfur compounds. It is a highly corrosive and toxic substance, and it reacts on contact with water to form chlorine-containing acids.
[
]
Chlorination of sulfur
is produced by the chlorination of either elemental 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 ...
or disulfur dichloride. The process occurs in a series of steps, some of which are:
:; ''ΔH'' = −58.2 kJ/mol
:; ''ΔH'' = −40.6 kJ/mol
The addition of to has been proposed to proceed via a mixed valence intermediate . undergoes even further chlorination to give , but this species is unstable at near room temperature. It is likely that several exist where ''n'' > 2.
Disulfur dichloride, , is a common impurity in .azeotrope
An azeotrope () or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be changed by simple distillation.Moore, Walter J. ''Physical Chemistry'', 3rd e Prentice-Hall 1962, pp. 140–142 This happens beca ...
of 99% purity. Sulfur dichloride loses chlorine slowly at room temperature, converting to disulfur dichloride and eventually higher sulfanes. Pure samples may be stored in sealed glass ampules which develop a slight positive pressure of chlorine, halting the decomposition.
Use of in chemical synthesis
is used in organic synthesis
Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...
. It adds to alkenes
In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins.
The Internationa ...
to give chloride-substituted thioethers. Illustrative is its addition to 1,5-cyclooctadiene to give a bicyclic thioether A well tested method for the production of the mustard gas bis(2-chloroethyl)sulfide, is the addition of ethylene to sulfur dichloride:[R. J. Cremlyn “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). .]
:
is also a precursor to several inorganic sulfur compounds. Treatment with fluoride salts gives via the decomposition of the intermediate sulfur difluoride. With , reacts to give "lower" sulfanes such as . oxidizes to .
Reaction with ammonia affords sulfur nitrides related to . Treatment of with primary amines gives sulfur diimides. One example is di-''t''-butylsulfurdiimide.
Safety considerations
hydrolyzes with release of HCl. Old samples contain .[
]
References
{{Chlorides
Sulfur chlorides
Sulfur(II) compounds