Silicon tetrafluoride
 | |
 | |
| Names | |
|---|---|
| IUPAC names
Tetrafluorosilane Silicon tetrafluoride | |
| Other names
Silicon fluoride Fluoro acid air | |
| Identifiers | |
7783-61-1  | |
| Jmol interactive 3D | Image |
| PubChem | 24556 |
| RTECS number | VW2327000 |
| UN number | 1859 |
| |
| Properties | |
| SiF4 | |
| Molar mass | 104.0791 g/mol |
| Appearance | colourless gas, fumes in moist air |
| Density | 1.66 g/cm3, solid (−95 °C) 4.69 g/L (gas) |
| Melting point | −90 °C (−130 °F; 183 K) |
| Boiling point | −86 °C (−123 °F; 187 K) |
| decomposes | |
| Structure | |
| tetrahedral | |
| 0 D | |
| Hazards | |
| Main hazards | toxic, corrosive |
| Safety data sheet | ICSC 0576 |
| NFPA 704 | |
| Lethal dose or concentration (LD, LC): | |
| LCLo (Lowest published) |
69,220 mg/m3 (rat, 4 hr)[1] |
| Related compounds | |
| Other anions |
Silicon tetrachloride Silicon tetrabromide Silicon tetraiodide |
| Other cations |
Carbon tetrafluoride Germanium tetrafluoride Tin tetrafluoride Lead tetrafluoride |
| Related compounds |
Hexafluorosilicic acid |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
verify (what is  ?) | |
| Infobox references | |
Silicon tetrafluoride or Tetrafluorosilane is the chemical compound with the formula SiF4. This tetrahedral molecule is notable for having a remarkably narrow liquid range (its boiling point is only 4 °C above its melting point). It was first synthesized by John Davy in 1812.[2]
Preparation
SiF
4 is a by-product of the production of phosphate fertilizers, resulting from the attack of HF (derived from fluorapatite protonolysis) on silicates. In the laboratory, the compound is prepared by heating BaSiF
6 above 300 °C, whereupon the solid releases volatile SiF
4, leaving a residue of BaF
2. The required BaSiF
6 is prepared by treating aqueous hexafluorosilicic acid with barium chloride.[3] The corresponding GeF
4 is prepared analogously, except that the thermal "cracking" requires 700 °C.[4]
SiF
4 can also be created by placing silicon dioxide in hydrofluoric acid using the following equation:
Uses
This volatile compound finds limited use in microelectronics and organic synthesis.[5]
Occurrence
Volcanic plumes contain significant amounts of silicon tetrafluoride. Production can reach several tonnes per day.[6] The silicon tetrafluoride is partly hydrolysed and forms hexafluorosilicic acid.
References
- ↑ "Fluorides (as F)". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
- ↑ John Davy (1812). "An Account of Some Experiments on Different Combinations of Fluoric Acid". Philosophical Transactions of the Royal Society of London 102: 352–369. doi:10.1098/rstl.1812.0020. ISSN 0261-0523. JSTOR 107324.
- ↑ Hoffman, C. J.; Gutowsky, H. S. "Silicon Tetrafluoride" Inorganic Syntheses McGraw-Hill: New York, Volume 4, pages 145-6, 1953.
- ↑ Hoffman, C. J.; Gutowsky, H. S. "Germanium Tetrafluoride" Inorganic Syntheses McGraw-Hill: New York, Volume 4, pages 147-8, 1953.
- ↑ Shimizu, M. "Silicon(IV) Fluoride" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. doi:10.1002/047084289X.rs011
- ↑ T. Mori, M. Sato, Y. Shimoike, K. Notsu (2002). "High SiF4/HF ratio detected in Satsuma-Iwojima volcano's plume by remote FT-IR observation" (PDF). Earth Planets Space 54: 249–256.
| ||||||||||
|