Sulfuryl chloride

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Sulfuryl chloride
IUPAC name
Sulfuryl chloride
Other names
Sulfonyl chloride
Sulfur dichloride dioxide
Sulfuric chloride
Sulfuroyl dichloride
Molar mass 134.9698 g/mol
Appearance Colorless liquid with a strong pungent odor
Yellowish upon standing
Odor Pungent, suffocating
Density 1.67 g/cm3 (at 20 °C)
Melting point −54.1 °C (−65.4 °F; 219.1 K)
Boiling point 69.4 °C (156.9 °F; 342.5 K)
Solubility Reacts with alcohols, amines, esters
Miscible with glacial acetic acid, benzene, carbon tetrachloride, chloroform, dichloromethane, toluene
Soluble in hydrogen cyanide, liq. SO2, SnCl4
Immiscible with conc. sulfuric acid
Vapor pressure 106.5 mmHg (at 20 °C)
393 kJ/mol
Safety data sheet ScienceLab
Flash point Non-flammable
Related compounds
Related compounds
Thionyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sulfuryl chloride is a water sensitive inorganic compound with the formula SO2Cl2. Sulfuryl chloride is sometimes confused with thionyl chloride (SOCl2), however the properties of the two chemicals are very different, as sulfuryl chloride is a source of chlorine, while thionyl chloride is a source of chloride ions.



Sulfuryl chloride reacts exothermically with water to form hydrogen chloride and sulfuric acid:

2 H2O + SO2Cl2 → 2 HCl + H2SO4

It will chlorinate various organic compounds, such as alkanes, alkenes, alkynes, aromatics, ethers. It will also chlorinate the metal center from organometallic compounds, when it is in a lower oxidation state.


Sulfuryl chloride is a colorless to yellowish liquid, with a strong poignant smell reminiscent of burned matches. It readily hydrolyzes in water and reacts with some organic solvents.


Sulfuryl chloride is sold by various chemical suppliers, but it is extremely difficult for the amateur chemist to acquire it.


Sulfuryl chloride can be made by reacting sulfur dioxide and chlorine. The reaction is generally done without a solvent. Activated carbon or graphite is used as a catalyst, though UV light can speed up the reaction.[1]

SO2 + Cl2 → SO2Cl2

If the reaction is done without a catalyst, at low temperatures, no product is obtained.[2]

It can also be prepared by reacting disulfur dichloride with sulfur dioxide, at 170 °C. Elemental sulfur is produced as a byproduct.[3]

S2Cl2 + SO2 → SO2Cl2 + 2 S

Chlorination of chlorosulfuric acid will yield sulfuryl chloride. Various reagents, such as antimony(III) chloride, bismuth chloride, tin(IV) chloride can be used. Yields are given as 90%.[4] If mercury or mercury(II) sulfate are used instead, the yield is only around 60%.[5][6]

4 SOCl2 + Hg → S2Cl2 + HgCl2 + 2 SO2Cl

Aluminium chloride will react with sulfur trioxide to yield sulfuryl chloride.[7][8]

Oxidation of thionyl chloride with certain metal oxides, like manganese dioxide, lead(II,IV) oxide, lead(IV) oxide, barium peroxide, also yields sulfuryl chloride. Reaction takes place at 150 °C over several hours:[9]

2 SOCl2 + MnO2 → SO2Cl2 + MnCl2 + SO2
4 SOCl2 + Pb3O4 → SO2Cl2 + 3 PbCl2 + 3 SO2
2 SOCl2 + PbO2 → S2Cl2 + PbCl2 + 3 SO2Cl2
2 SOCl2 + BaO2 → S2Cl2 + BaCl2 + 3 SO2Cl2

If mercury(II) oxide is used, a large excess of thionyl chloride must be used. If equimolar amounts of HgO and thionyl chloride are used instead, only sulfur dioxide is produced.[10]

5 SOCl2 + HgO → S2Cl2 + HgCl2 + 3 SO2Cl2
SOCl2 + HgO → HgCl2 + SO2

A less known route is given in literature as the reaction between sulfur trioxide and chromyl chloride.[11][12]

SO3 + CrO2Cl2 → SO2Cl2 + CrO3

Thermal decomposition of sodium chlorosulfate (sodium salt of chlorosulfuric acid) is claimed to yield sulfuryl chloride:[13]

2 NaSO3Cl → SO2Cl2 + Na2SO4

Other sources indicate that sodium pyrosulfate is produced as side product.[14][15]


  • Make chlorobenzene
  • Make alkyl chlorides



Sulfuryl is extremely corrosive and toxic. It fumes in (moist) air and hydrolyzes in water.


Sulfuryl chloride should be stored in glass bottles, preferably amber glass, away from any moisture, best in a corrosive chemicals cabinet.


Sulfuryl chloride can be neutralized with an alkaline solution. The reaction will release plenty of corrosive fumes, so it's best to do this outside.


  1. F. Fehér (1963). "Sulfuryl Chloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY,NY: Academic Press. pp. 382–384
  2. Schulze, H.; Journal fuer Praktische Chemie (Leipzig); vol. 24; (1881); p. 168 - 183
  3. Besson, A.; Fournier, L.; Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences; vol. 150; (1910); p. 1752 - 1754
  4. Ruff, O.; Ber.; vol. 34; (1901); p. 3509 - 3515
  5. Bert, L.; Bulletin de la Societe Chimique de France; vol. 31; (1922); p. 1264 - 1270
  6. North, H. B.; Journal of the American Chemical Society; vol. 32; (1910); p. 184 - 187
  7. Rose, H.; Annalen der Physik (Weinheim, Germany); vol. 44; (1838); p. 291 - 327
  8. Beckmann, E.; Z. Anorg. Chem.; vol. 77; (1912); p. 90 - 102 ; (from Gmelin)
  9. H. B. North and A. M. Hageman, J. Am. Chem. Soc. 1913, 35, 5, 543–546
  10. North, H. B.; Journal of the American Chemical Society; vol. 32; (1910); p. 184 - 187
  11. S: MVol.B3; 131, page 1807 - 1808; (from Gmelin)
  12. Luchinskii, G. P.; Likhacheva, A. I.; Zhurnal obshchei Khim. (russ.); vol. 7; (1937); p. 405 - 414
  13. Luchinskii, G. P.; Zhurnal obshchei Khim. (russ.); vol. 8; (1938); p. 1864 - 1869
  14. Puskaric, E.; Heubel, J.; Comptes Rendus des Seances de l'Academie des Sciences, Serie C: Sciences Chimiques; vol. 267; (1968); p. 965 - 967
  15. Puskaric, E.; Jaeger, R. de; Heubel, J.; Revue de Chimie Minerale; vol. 12; (1975); p. 374 - 381

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