Tetramethylsilane
Encyclopedia : T : TE : TET : Tetramethylsilane
| Tetramethylsilane | |
|---|---|
  
| |
| General | |
| Systematic name | Tetramethylsilane |
| Other names | TMS |
| Molecular formula | (CH3)4Si |
| SMILES | C[Si](C)(C)C |
| Molar mass | 88.2248 g/mol |
| Appearance | Colourless liquid. |
| CAS number | |
| Properties | |
| Density and phase | 0.65 g/cm-3, liquid. |
| Solubility in water | ? g/100 ml (?°C) |
| Melting point | -99.06°C (174.09 K) |
| Boiling point | 26.6°C (299.75 K) |
| Viscosity | ? cP at ?°C |
| Structure | |
| Molecular shape | Tetrahedral |
| Dipole moment | 0 D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Highly flammable. |
| NFPA 704 | |
| Flash point | -28°C |
| R/S statement | R: R20, R36, R37, R38. S: S16, S24/25, S7/9. |
| RTECS number | VV5705400 |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | trimethylsilyl |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) [Chemical infoboxInfobox disclaimer and references] | |
Tetramethylsilane is a chemical compound whose molecular structure is a derivative of silane (SiH4) with four methyl groups substituted for the four hydrogen atoms in it. The acronym TMS is very commonly used for this highly volatile organic compound which contains a silicon atom in the center. Tetramethylsilane has the chemical formula C4H12Si and the chemical structure shown in the infobox. A structural chemical formula could be written as Si(CH3)4 where -CH3 is a methyl group.
Uses
Tetramethylsilane is used as an internal standard for calibrating chemical shift in 1H and 13C NMR spectroscopy. Because all twelve hydrogen atoms in a tetramethylsilane molecule are equivalent, they show up as a singlet peak in an 1H NMR spectrum. The chemical shift of this singlet is considered to be δ0.0 in the spectrum and all other chemical shifts are determined relative to it. The silicon in tetramethylsilane shifts its 1H NMR signal upfield. The vast majority of compounds studied by 1H NMR have hydrogen peaks downfield of the tetramethylsilane peak, so there is usually no interefence between this standard peak and the sample peaks, and the tetramethylsilane singlet can usually easily be identified for the chemical shift calibration.
Similarly, all four carbon atoms in a tetramethylsilane molecule are equivalent. In a fully decoupled 13C NMR spectrum, the carbon in the tetramethylsilane also shows up as a singlet, allowing for easier identification. The chemical shift of this singlet is also set to be δ0.0 in the 13C spectrum and all other chemical shifts are determined relative to it.
A supply of tetramethylsilane is usually kept as a refrigerated liquid because otherwise, it could easily evaporate away. The symmetry of the tetramethylsilane molecule makes it a non-polar compound.
Tetramethylsilane is used in chemical vapor deposition processes to create thin layers of silicon dioxide or silicon carbide.
External links
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
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