Trimethylsulfonium

Trimethylsulfonium

Names
Other names Trimesium
Identifiers
CAS Number	676-84-6
ChemSpider	1115
Jmol 3D model	Interactive image
SMILES C[S+](C)C
Properties
Chemical formula	C3H9S+
Molar mass	77.17 g/mol
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Trimethylsulfonium (systematically named trimethylsulfanium and trimethylsulfur(1+)) is an organic cation with the chemical formula (CH₃)₃S⁺ (also written as C
₃H
₉S⁺
). It is the simplest sulfonium cation.

Compounds

Several salts of trimethylsulfonium are known:

Salt	Molecular formula	Chemical formula	Molecular weight (g/mol)	Properties
Trimethylsulfonium chloride	(CH3)3SCl	C3H9ClS	112.5	Colorless crystals, decompose at 100 °C, very soluble in ethanol, very hygroscopic.
Trimethylsulfonium bromide	(CH3)3SBr	C3H9BrS	157	Colorless crystals from H2O. Decomposes at 172 °C, melts in a sealed tube at 201-201 °C, reacts in neutral aqueous solution.
Trimethylsulfonium iodide	(CH3)3SI	C3H9IS	204	Colorless crystals from ethanol, decomposes at 203-207 °C.

Preparation

Sulfonium compounds can be synthesised by treating a suitable alkyl halide with a thioether. For example, the reaction of dimethyl sulfide with iodomethane yields trimethylsulfonium iodide:

CH₃–S–CH₃ + CH₃–I → (CH₃)₃SI

See also

• Onium compounds