Tetramethylsilane
[CAS# 75-76-3]

Identification

• Classification: Chemical reagent >> Organic reagent >> Silane
• Name: Tetramethylsilane
• Synonyms: TMS
• Molecular Formula: C₄H₁₂Si
• Molecular Weight: 88.22
• CAS Registry Number: 75-76-3
• EC Number: 200-899-1
• SMILES: C[Si](C)(C)C

Properties

• Density: 0.648
• Melting point: -99 ºC
• Boiling point: 26-28 ºC
• Refractive index: 1.3585
• Flash point: -27 ºC
• Water solubility: 0.02 g/L (25 ºC)

Safety Data

• Hazard Symbols: GHS02;GHS07;GHS09 DangerGHS02
• Hazard Statements: H224-H302-H411
• Precautionary Statements: P210-P233-P240-P241-P242-P243-P264-P270-P273-P280-P301+P317-P303+P361+P353-P330-P370+P378-P391-P403+P235-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	1	H224
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Flammable liquids	Flam. Liq.	2	H225

• Transport Information: UN 2749

Discovory and Applicatios

Tetramethylsilane is an organosilicon compound consisting of a silicon atom bound to four methyl groups, forming a highly symmetrical and chemically robust molecule. Its development and characterization emerged from the early expansion of organosilicon chemistry in the mid-twentieth century, when systematic studies of silicon–carbon bonding produced a series of fully substituted alkylsilanes. The compound’s physical simplicity, chemical neutrality, and volatility soon made it an important benchmark substance in analytical chemistry.

Its most widely recognized application is in nuclear magnetic resonance spectroscopy. The compound’s structural uniformity leads all twelve hydrogen atoms to experience the same magnetic environment, producing a single sharp resonance. In proton NMR, this peak is conventionally assigned the zero-ppm position, providing a universal reference point that allows direct comparison of spectra across instruments and laboratories. A similar function is served in carbon-13 NMR, where tetramethylsilane again yields a single reference signal. The adoption of this standard facilitated the establishment of consistent chemical shift scales, enabling the development of the extensive spectral libraries used in organic, pharmaceutical, and materials research.

The selection of tetramethylsilane as a reference standard arose from several experimentally confirmed advantages. Its chemical inertness prevents reaction with most analytes, ensuring that sample composition remains unaltered. Its low boiling point and miscibility with common organic solvents allow for easy incorporation into sample preparations without introducing significant background signals. Furthermore, the absence of electronegative substituents or structural asymmetry ensures minimal perturbation of magnetic environments in solution, maintaining the reliability of the reference peak.

Outside its analytical use, tetramethylsilane serves as a precursor in the synthesis of other organosilicon compounds. Controlled chlorination yields chloromethylsilanes, which in turn can be transformed into functionalized silanes for use in materials modification, polymer chemistry, and surface treatments. These transformations form part of a broader family of reactions that explore how substitution patterns at silicon influence reactivity, stability, and the formation of silicon–oxygen or silicon–carbon frameworks.

In industrial research, tetramethylsilane has been used as a feedstock for processes that require highly volatile silicon-containing precursors. In plasma-enhanced chemical vapor deposition and related thin-film methodologies, the compound can generate silicon-containing fragments under energetic conditions, contributing to the formation of protective coatings or dielectric layers. Its fragmentation chemistry, documented through gas-phase studies, has assisted in mapping decomposition pathways of small organosilicon molecules under ionization or plasma exposure.

The compound has also served as a reference material in mass spectrometry. Because its ionization behavior is well characterized, its fragmentation pattern has been used to calibrate relative intensity scales and to verify instrument performance. Its spectral simplicity allows it to act as a clean reference without overlapping peaks from common organic analytes.

Research into tetramethylsilane and related tetraalkylsilanes has contributed significantly to the understanding of silicon’s behavior in organic environments. Comparative studies with carbon analogs have highlighted differences in bond energies, steric effects, and conformational preferences. These investigations have shaped the theoretical and experimental foundation of modern organosilicon chemistry, which supports applications across adhesives, elastomers, surface coatings, semiconductor processing, and specialty polymers.

Today, tetramethylsilane remains an indispensable component of NMR spectroscopy and a stable, well-understood model compound for examining silicon-centered bonding. Its role across analytical, preparative, and industrial domains demonstrates how structurally simple molecules can influence broad areas of chemical research and application.

References

Colclough, M. E. (1966). The mass spectra of tetramethylsilane and related compounds. Organic Mass Spectrometry (now Rapid Communications in Mass Spectrometry) 1, 109–118. [https://doi.org/10.1002/oms.1210010116](https://doi.org/10.1002/oms.1210010116)