Tetramethylsilane

"Tetramethylsilane (abbreviated as TMS) is the chemical compound with the formula Si(CH₃)₄. It is the simplest tetraorganosilane. Like all silanes, the TMS framework is tetrahedral. TMS is a building block in organometallic chemistry but also finds use in diverse niche applications."

"TMS is a by-product of the production of methyl chlorosilanes, SiCl_x(CH₃)_4−x, via the direct process of reacting methyl chloride with silicon. The more useful products of this reaction are those for x = 1, 2, and 3."

"TMS undergoes deprotonation upon treatment with butyllithium to give (H₃C)₃SiCH₂Li. The latter, trimethylsilylmethyl lithium, is a relatively common alkylating agent."

Tetramethylsilane is the accepted internal standard for calibrating chemical shift for ¹H, ¹³C and ²⁹Si NMR spectroscopy in organic solvents (where TMS is soluble). In water, where it is not soluble, sodium salts of DSS, 2,2-dimethyl-2-silapentane-5-sulfonate, are used instead. Because of its high volatility, TMS can easily be evaporated, which is convenient for recovery of samples analyzed by NMR spectroscopy.