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'''Silicon tetrafluoride''' or '''Tetrafluorosilane''' is the [[chemical compound]] with the formula [[silicon|Si]][[Fluorine|F]]<sub>4</sub>. This tetrahedral molecule is striking because it has a remarkably narrow liquid range (its boiling point is only 4&nbsp;°C above its melting point). It was first synthesized by [[John Davy (chemist)|John Davy]] in 1812.<ref>{{cite journal
'''Silicon tetrafluoride''' or '''Tetrafluorosilane''' is the [[chemical compound]] with the formula [[silicon|Si]][[Fluorine|F]]<sub>4</sub>. This tetrahedral molecule is notable for having a remarkably narrow liquid range (its boiling point is only 4&nbsp;°C above its melting point). It was first synthesized by [[John Davy (chemist)|John Davy]] in 1812.<ref>{{cite journal
| title = An Account of Some Experiments on Different Combinations of Fluoric Acid
| title = An Account of Some Experiments on Different Combinations of Fluoric Acid
| author = John Davy
| author = John Davy

Revision as of 17:31, 8 February 2010

Silicon tetrafluoride
Silicon tetrafluoride
Silicon tetrafluoride
Names
IUPAC names
Tetrafluorosilane
Silicon tetrafluoride
Other names
Silicon fluoride
Fluoro acid air
Identifiers
3D model (JSmol)
ECHA InfoCard 100.029.104 Edit this at Wikidata
RTECS number
  • VW2327000
UN number 1859
  • FSi(F)(F)F
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
Boiling point −86 °C
decomposes
Structure
tetrahedral
0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
toxic, corrosive
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3
0
2
Related compounds
Other anions
Silicon tetrachloride
Silicon tetrabromide
Silicon tetraiodide
Other cations
Carbon tetrafluoride
Germanium tetrafluoride
Tin tetrafluoride
Lead tetrafluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.[1]

Preparation

SiF4 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 BaSiF6 >300 °C, whereupon the solid releases volatile SiF4, leaving a residue of BaF2. The required BaSiF6 is prepared by treating aqueous fluorosilicic acid with barium chloride.[2] The corresponding GeF4 is prepared analogously, except that the thermal "cracking" requires 700 °C.[3]

Uses

This volatile compound finds limited use in microelectronics and organic synthesis.[4]

Occurrence

Volcanic plumes contain significant amounts of silicon tetrafluoride, the daily production can reach several tonnes per day.[5] The silicon tetrafluoride is partly hydrolysed and forms hexafluorosilicic acid.

References

  1. ^ 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.
  2. ^ Hoffman, C. J.; Gutowsky, H. S. “Silicon Tetrafluoride” Inorganic Syntheses McGraw-Hill: New York, Volume 4, pages 145-6, 1953.
  3. ^ Hoffman, C. J.; Gutowsky, H. S. "Germanium Tetrafluoride” Inorganic Syntheses McGraw-Hill: New York, Volume 4, pages 147-8, 1953.
  4. ^ Shimizu, M. "Silicon(IV) Fluoride" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. DOI: 10.1002/047084289X.rs011
  5. ^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)