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IUPAC name
Carbonothioyl dichloride
Other names
Thiophosgene; Thiocarbonyl chloride; Carbonothioic dichloride
3D model (JSmol)
ECHA InfoCard 100.006.675
RTECS number XN2450000
Molar mass 114.98 g/mol
Appearance Red liquid
Density 1.50 g/cm3
Boiling point 70 to 75 °C (158 to 167 °F; 343 to 348 K)
Solubility in other solvents polar organic solvents
rxn with amines and alcohols
-50.6·10−6 cm3/mol
planar, sp2, C2v
Main hazards Highly toxic
Flash point 62 °C (144 °F; 335 K)
Related compounds
Related compounds
Thiocarbonyl fluoride
Thiocarbonyl bromide
Sulfur dichloride
thionyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Thiophosgene is a red liquid with the formula CSCl2. It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse organic syntheses.[1]

Preparation of CSCl2[edit]

CSCl2 is prepared in a two-step process from carbon disulfide. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride (perchloromethyl mercaptan), CCl3SCl:

CS2 + 3 Cl2 → CCl3SCl + S2Cl2

The chlorination must be controlled as excess chlorine converts trichloromethanesulfenyl chloride into carbon tetrachloride. Steam distillation separates the trichloromethanesulfenyl chloride, a rare sulfenyl chloride, and hydrolyzes the sulfur monochloride. Reduction of trichloromethanesulfenyl chloride produces thiophosgene:

CCl3SCl + M → CSCl2 + MCl2

Typically, tin is used for the reducing agent M.[2]

Uses of CSCl2[edit]

CSCl2 is mainly used to prepare compounds with the connectivity CSX2 where X = OR, NHR.[3] Such reactions proceed via intermediate such as CSClX. Under certain conditions, one can convert primary amines into isothiocyanates. CSCl2 also serves as a dienophile to give, after reduction 5-thiacyclohexene derivatives. Thiophosgene is also known as the appropriate reagent in Corey-Winter synthesis for stereospecific conversion of 1,2-diols into olefins.[4]

Safety considerations[edit]

CSCl2 is considered highly toxic.


  1. ^ Manchiu D. S. Lay, Mitchell W. Sauerhoff And Donald R. Saunders "Carbon Disulfide" in Ullmann's Encyclopedia Of Industrial Chemistry, 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a05_185
  2. ^ Dyson, G. M. (1926). "Thiophosgene" (PDF). Org. Synth. 6: 86. doi:10.15227/orgsyn.006.0086. ; Coll. Vol., 1, p. 506 
  3. ^ Pascual, Roxana Martinez "Thiophosgene" Synlett 2015, vol. 26, pp. 1776-1777. doi:10.1055/s-0034-1380659
  4. ^ Sharma, S. (1978). "Thiophosgene in Organic Synthesis". Synthesis. 1978 (11): 803–820. doi:10.1055/s-1978-24896. 

Further reading[edit]

  • Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils, ed., Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN 0-12-352651-5