Boron trifluoride
Encyclopedia : B : BO : BOR : Boron trifluoride
| Boron trifluoride | |
|---|---|
| |
| Systematic name | Boron trifluoride |
| Molecular formula | BF3 |
| Molar mass | 67.81 g/mol |
| Density | 2.178 g/dm3 |
| Relative density (air = 1) | 2.42 |
| Solubility (water) | decomposes |
| Melting point | -126 °C |
| Boiling point | -100.3 °C |
| CAS number | [xx-xx-xx] |
| [Chemical infoboxDisclaimer and references] | |
Boron trifluoride (BF3, trifluoroborane) is a pungent pale yellow highly toxic gas. In moist air it forms white fumes. Boron trifluoride can be handled as a liquid in a Lewis acid-base adduct with diethyl ether. The molecule BF3 consists of boron and fluorine in a trigonal planar geometry. Its CAS number is [7637-07-2][link] and its EINECS number is 231-569-5. It is nonflammable. It is destructive to eyes and mucous membranes. Its melting point is -126 °C and its boiling point is -100.3 °C.
Boron trifluoride is corrosive. Metals for equipment handling boron trifluoride can be eg. stainless steel, monel, and hastelloy. In presence of moisture it corrodes steel, including stainless steel. It reacts with polyamides. Polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polypropylene show satisfactory resistance. The lubricants used in the equipment should be fluorocarbon based, as boron trifluoride reacts with the hydrocarbon-based ones. [link]
The BF3 molecule, although composed of highly polar covalent bonds, is nonpolar because of the boron atom's sp2 hybridisation which produce three symmetrical orbitals. Boron is electron deficient and in chemical reactions BF3 is a Lewis acid, for example reacting with fluorides to form tetrafluoroborate salts:
- CsF + BF3 → CsBF4
Boron trifluoride also forms acceptor compounds with such Lewis bases as ammonia and ethers.
Uses
- applied as dopant in ion implantation
- as a p-type dopant for epitaxially grown silicon
- initiates polymerisation reactions of unsaturated compounds. Example polyethers
- as a catalyst in some isomerization, alkylation, esterification, condensation, and other reactions.
- used in sensitive neutron detectors
References
External links
- http://www.osha.gov/dts/chemicalsampling/data/CH_221700.html
- http://www.cdc.gov/niosh/ipcsneng/neng0231.html
- [National Pollutant Inventory - Boron and compounds fact sheet]
- [National Pollutant Inventory - Fluoride and compounds fact sheet]
- 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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