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 . This cherry-red liquid is the simplest sulfur chloride and one of the most common, and it is used as a precursor to
organosulfur
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur ...
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 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
Mixed valence complexes contain an chemical element, element which is present in more than one oxidation state. Well-known mixed valence compounds include the Creutz–Taube complex, Prussian blue, and molybdenum blue. Many solids are mixed-vale ...
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 the most common impurity in . Separation of from is possible via distillation with
to form an
azeotrope
An azeotrope () or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation.Moore, Walter J. ''Physical Chemistry'', 3rd e Prentice-Hall 1962, pp. 140–142 This ...
of 99% purity, however sulfur dichloride loses chlorine slowly at room temperature and reverts to disulfur dichloride. 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. It adds to
alkenes
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
to give chloride-substituted thioethers. Illustrative applications are its addition to
1,5-cyclooctadiene to give a bicyclic
thioether
In organic chemistry, an organic sulfide (British English sulphide) or thioether is an organosulfur functional group with the connectivity as shown on right. Like many other sulfur-containing compounds, volatile sulfides have foul odors. A su ...
and
ethylene to give
sulfur mustard .
[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
Sulfur difluoride is an inorganic compound with the chemical formula SF2. It can be generated by the reaction of sulfur dichloride and potassium fluoride or mercury(II) fluoride at low pressures:
:SCl2 + 2 KF → SF2 + 2 KCl
:SCl2 + HgF2 → SF2 + ...
. With , reacts to give "lower" sulfanes such as .
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
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolysi ...
with release of
HCl. Old samples contain .
References
{{Chlorides
Sulfur chlorides
Sulfur(II) compounds