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 betwee ...

. 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 Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

disulfur dichloride Disulfur dichloride is the inorganic compound of sulfur and chlorine with the Chemical formula, formula S2Cl2. Some alternative names for this compound are ''sulfur monochloride'' (the name implied by its empirical formula, SCl), ''disulphur dich ...

. 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 Disulfur dichloride is the inorganic compound of sulfur and chlorine with the Chemical formula, formula S2Cl2. Some alternative names for this compound are ''sulfur monochloride'' (the name implied by its empirical formula, SCl), ''disulphur dich ...

, , 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 An ampoule (also ampul and ampule) is a small sealed vial which is used to contain and preserve a sample, usually a solid or liquid. Ampoules are usually made of glass. Modern ampoules are most commonly used to contain pharmaceuticals and chem ...

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 special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

. 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 Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula , specifically . There are three configurational isomers with this structure, that differ by the arrangement of the four C–C single bonds adjacent to the double bonds. Each ...

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 Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

to give

sulfur mustard Mustard gas or sulfur mustard is a chemical compound belonging to a family of cytotoxic and blister agents known as mustard agents. The name ''mustard gas'' is technically incorrect: the substance, when dispersed, is often not actually a gas, b ...

.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 hydrolysis ...

with release of

HCl HCL may refer to: Science and medicine * Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia * Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development * Hollow-cathode lamp, a spe ...

. Old samples contain .

References

{{Chlorides Sulfur chlorides Sulfur(II) compounds