From the Merck Index:
Monograph number: 9153
Title: Sulfuryl Chloride.
CAS Registry number: [7791-25-5]
Molecular formula: Cl2O2S
Molecular weight: 134.97
Composition: Cl 52.53%, O 23.71%, S 23.76%.
Line formula: SO2Cl2.
Literature references: Prepd by passing a mixture of dry sulfur dioxide and chlorine through activated charcoal (other catalysts, such as camphor, can be used): Danneel, Angew. Chem. 39, 1553 (1926); Durrans, J. Soc. Chem. Ind. 45, 347 (1926); Meyer, Angew. Chem. 44, 41 (1931); Danneel, Hesse, Z. Anorg. Allgem. Chem. 212, 214 (1933); Allen, Maxson, Inorg. Syn. 1, 114 (1939).
Properties: Colorless, mobile liquid, very pungent odor. Even the vapors are corrosive to human skin and mucous membranes. Turns yellow upon prolonged standing because of slight dissociation into SO2 and Cl2. d420 1.6674. d40 1.7045. mp -54.1 deg (also given as -46 deg). bp 69.3 deg. nD20 1.4437. Dipole moment 1.86. Trouton constant 20.7. Slowly dec by water, forming H2SO4 and HCl. With ice-cold water it forms a hydrate,
SO2Cl2.15H2O, resembling camphor in appearance. Violent
reaction on contact with alkalies. Miscible with benzene, toluene, ether, glacial acetic acid, other organic solvents.
Melting point: -54.1; -46
Boiling point: 69.3
Density: 1.6674; 1.7045
Refraction: 1.4437
USE: Chlorinating and sulfonating or chlorosulfonating agent in organic syntheses, e.g., in the manufacture of chlorophenol and chlorothymol. Has been used in war gas formulations.