Disulfuryl chloride

Disulfuryl chloride is an inorganic compound of sulfur, chlorine, and oxygen with the chemical formula S₂O₅Cl₂.^[1] This is the anhydride of chlorosulfuric acid.

Disulfuryl chloride

Names
Other names Pyrosulfuryl chloride Disulfur pentoxydichloride Sulfur pentoxydichloride
Identifiers
CAS Number	7791-27-7
3D model (JSmol)	Interactive image
ChemSpider	23051
PubChem CID	24649
UNII	DKB8YHP7JA
UN number	1817 (PYROSULFURYL CHLORIDE)
CompTox Dashboard (EPA)	DTXSID90999111
InChI InChI=1S/Cl2O5S2/c1-8(3,4)7-9(2,5)6 Key: NNTJKSMVNWGFTB-UHFFFAOYSA-N
SMILES O=S(=O)(OS(=O)(=O)Cl)Cl
Properties
Chemical formula	Cl2O5S2
Molar mass	215.02 g·mol−1
Appearance	colorless liquid
Density	1.84 g/cm3
Melting point	–37 °C
Boiling point	152.5 °C
Solubility in water	reacts with water
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Careful heating of sulfur trioxide and carbon tetrachloride:^[2]

2SO₃ + CCl₄ → S₂O₅Cl₂ + COCl₂

There are also other known methods that do not produce phosgene as a by-product, for example mixing sulfur trioxide and sulfuryl chloride:

SO₃ + SO₂Cl₂ → S₂O₅Cl₂

Physical properties

The compound appears as a dense, very refractive, colorless liquid with a pungent odor, insoluble in cold water, and prone to hydrolysis.^[3][4] Its tendency to smoke in air is low when the compound is pure, while the smoke increases with the presence of chlorosulfuric acid impurities, which are more prone to hydrolysis.

Chemical properties

It slowly drools on contact with water:^[5]

S₂O₅Cl₂ + 3H₂O → 2H₂SO₄ + 2HCl↑

Prolonged boiling or heating to 250 °C results in dissociation into sulfur trioxide, sulfur dioxide, and chlorine.^[2]

Uses

The compound is used in organic synthesis and as a chlorinating agent.^[5]

See also

• Disulfuryl fluoride
• Disulfuryl chloride fluoride
• Peroxydisulfuryl difluoride
• Trisulfuryl chloride