Tetramethylsilane (TMS): Used as a chemical shift reference in ¹H-NMR and ¹³C-NMR spectroscopy. By definition, TMS has a chemical shift of 0.00 ppm.

Molecular structure of tetramethylsilane (TMS).

Simulated 1H-NMR spectrum with TMS reference.		Simulated 13C-NMR spectrum with TMS reference.