Sulfur dichloride

Sulfur dichloride
IUPAC name

Sulpur dichloride
Sulfur(II) chloride
Dichlorosulfane
Other names

Sulpur chloride
Identifiers
CAS number 10545-99-0 Y
EC number 234-129-0
UN number 1828
RTECS number WS4500000
Jmol-3D images Image 1
Properties
Molecular formula SCl2
Molar mass 102.97 g mol−1
Appearance red liquid with pungent odour
Density 1.621 g cm−3, liquid
Melting point

−121.0 °C, 152.2 K, -185.8 °F
Boiling point

59 °C, 332 K, 138 °F (decomp.)
Solubility in water hydrolysis
Refractive index (nD) 1.5570
Structure
Coordination
geometry		 C2v
Molecular shape Bent
Hazards
MSDS ICSC 1661
EU Index 016-013-00-X
EU classification Corrosive (C)
Irritant (Xi)
Dangerous for the environment (N)
R-phrases R14, R34, R37, R50
S-phrases (S1/2), S26, S45, S61
NFPA 704
1
3
2
W
Autoignition
temperature		 234 °C
Related compounds
Related Disulfur dichloride
Thionyl chloride
Sulfuryl chloride
Related compounds Sulfur tetrafluoride
Sulfur hexafluoride
Disulfur dibromide
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sulfur dichloride is the chemical compound with the formula SCl2. This cherry-red liquid is the simplest sulfur chloride and one of the most common. It is used as a precursor to organosulfur compounds.[1]

Contents

Chlorination of sulfur

SCl2 is produced by the chlorination of either elemental sulfur or disulfur dichloride. The process occurs in a series of steps, some of which are:

S8 + 4 Cl2 → 4 S2Cl2; ΔH = −58.2 kJ/mol
S2Cl2 + Cl2 → 2 SCl2; ΔH = −40.6 kJ/mol

The addition of Cl2 to S2Cl2 has been proposed to proceed via a mixed valence intermediate Cl3S-SCl. SCl2 undergoes even further chlorination to give SCl4, but this species is unstable at near room temperature. It is likely that several SxCl2 exist where x > 2.

Disulfur dichloride, S2Cl2, is the most common impurity in SCl2. Separation of SCl2 from S2Cl2 is possible via distillation with PCl3 to form an azeotrope of 99% purity

Use of SCl2 in chemical synthesis

SCl2 is also a precursor to several inorganic sulfur compounds. Treatment with fluoride salts gives SF4. Reaction with ammonia affords sulfur nitrides related to S4N4. With H2S, SCl2 reacts to give "lower" sulfanes such as S3H2.

Safety considerations

SCl2 hydrolyzes with release of HCl. Old samples contain Cl2.

References

  1. ^ Schmidt, M.; Siebert, W. "Sulphur" Comprehensive Inorganic Chemistry Vol. 2, ed. A.F. Trotman-Dickenson. 1973.
  2. ^ Bishop, Roger (1992), "9-Thiabicyclo[3.3.1]nonane-2,6-dione", Org. Synth. 70: 120, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv9p0692 ; Coll. Vol. 9: 692 
  3. ^ R. J. Cremlyn “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0 471 95512 4.