Tetramethylsilane

Tetramethylsilane (TMS) is a chemical compound with the formula Si(CH3)4. It is the simplest tetraorganosilane and an archetype for the organosilanes, compounds containing carbon-silicon bonds. TMS is a building block in organometallic chemistry but also finds use in diverse niche applications.

Structure and bonding[edit | edit source]

Tetramethylsilane is tetrahedral in its molecular geometry, reflecting the tetrahedral coordination geometry about silicon that is common in organosilicon chemistry. The Si-C bond length is 186 pm, and the C-Si-C bond angle is 111°. The Si-C bond strength is 318 kJ/mol, which is stronger than the Si-O bond in the silicon mineral quartz (SiO2), reflecting the greater stability of the Si-C bond.

Synthesis and reactions[edit | edit source]

Tetramethylsilane is prepared by the reaction of methyl chloride with silicon in the presence of a catalyst, such as copper: Si + 4 CH3Cl → Si(CH3)4 + 4 Cl−

Tetramethylsilane undergoes reactions typical of other tetraorganosilanes. It can be converted to silicon tetrachloride by reaction with chlorine: Si(CH3)4 + 4 Cl2 → SiCl4 + 4 CH3Cl

Applications[edit | edit source]

Tetramethylsilane is commonly used as a standard in 1H NMR spectroscopy. It is also used as a precursor to various silicon-containing polymers and ceramics.