Sulfur dichloride

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Sulfur dichloride

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Template:Longitem	Template:Unbulleted list
ChEBI	Template:Unbulleted list
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RTECS number	Template:Unbulleted list
UN number	1828
Template:Longitem	Template:Chem2
Molar mass	Template:Chem molar mass
Appearance	Cherry-red liquid
Odor	Pungent
Density	1.621 g/cm3
Melting point	Template:Chembox CalcTemperatures
Boiling point	Template:Chembox CalcTemperatures
Template:Longitem	−49.4·10−6 cm3/mol
Template:Longitem	1.5570
Template:Longitem	C2v
Template:Longitem	Bent
NFPA 704 (fire diamond)	Template:NFPA 704 diamond
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Sulfur dichloride is the chemical compound with the formula Template:Chem2. 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

Template:Chem2 is produced by the chlorination of either elemental sulfur or disulfur dichloride. The process occurs in a series of steps, some of which are:

Template:Chem2; ΔH = −58.2 kJ/mol

Template:Chem2; ΔH = −40.6 kJ/mol

The addition of [[chlorine|Template:Chem2]] to Template:Chem2 has been proposed to proceed via a mixed valence intermediate Template:Chem2. Template:Chem2 undergoes even further chlorination to give [[SCl4|Template:Chem2]], but this species is unstable at near room temperature. It is likely that several Template:Chem2 exist where n > 2.

Disulfur dichloride, Template:Chem2, is a common impurity in Template:Chem2. Separation of Template:Chem2 from Template:Chem2 is possible via distillation with [[Phosphorus trichloride|Template:Chem2]] to form an azeotrope 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 Template:Chem2 in chemical synthesis

Template:Chem2 is used in organic synthesis. It adds to alkenes 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:

Template:Chem2

Template:Chem2 is also a precursor to several inorganic sulfur compounds. Treatment with fluoride salts gives [[Sulfur tetrafluoride|Template:Chem2]] via the decomposition of the intermediate sulfur difluoride. With Template:Chem2, Template:Chem2 reacts to give "lower" sulfanes such as Template:Chem2. Template:Chem2 oxidizes Template:Chem2 to Template:Chem2.

Reaction with ammonia affords sulfur nitrides related to [[tetrasulfur tetranitride|Template:Chem2]]. Treatment of Template:Chem2 with primary amines gives sulfur diimides. One example is di-t-butylsulfurdiimide.

Safety considerations

Template:Chem2 hydrolyzes with release of HCl. Old samples contain Template:Chem2.