Silicon tetrafluoride

Silicon tetrafluoride
Names
	IUPAC names Tetrafluorosilane; Silicon tetrafluoride
	Other names Silicon fluoride; Fluoro acid air
Identifiers
CAS Number	7783-61-1 ;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.029.104
PubChem CID	24556;
RTECS number	VW2327000;
UNII	K60VCI56YO ;
UN number	1859
CompTox Dashboard (EPA)	DTXSID0064830 ;
	show SMILES
Properties
Chemical formula	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	−95.0 °C (−139.0 °F; 178.2 K)
Boiling point	−90.3 °C (−130.5 °F; 182.8 K)
Solubility in water	decomposes
Structure
Molecular shape	tetrahedral
Dipole moment	0 D
Hazards
Main hazards	toxic, corrosive
Safety data sheet	ICSC 0576
NFPA 704 (fire diamond)	3 0 2 W
	Lethal dose or concentration (LD, LC):
LCLo (lowest published)	69,220 mg/m3 (rat, 4 hr)
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).
	(what is ?)
	Infobox references

Silicon tetrafluoride or tetrafluorosilane is the chemical compound with the formula SiF₄. This colorless compound is notable for having a narrow liquid range: its boiling point is only 4 °C above its melting point. It was first synthesized by John Davy in 1812.^[3] It is a tetrahedral molecule.

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, which are present as impurities in the phosphate rock. 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.^[4] The corresponding GeF
₄ is prepared analogously, except that the thermal "cracking" requires 700 °C.^[5] SiF
₄ can in principle also be generated by the reaction of silicon dioxide and hydrofluoric acid, but this process tends to give hexafluorosilicic acid:

6 HF + SiO₂ → H₂SiF₆ + 2 H₂O

Uses[]

This volatile compound finds limited use in microelectronics and organic synthesis.^[6]

Occurrence[]

Volcanic plumes contain significant amounts of silicon tetrafluoride. Production can reach several tonnes per day.^[7] Some amounts are also emitted from spontaneous coal fires.^[8] The silicon tetrafluoride is partly hydrolysed and forms hexafluorosilicic acid.

References[]

^ Jump up to: ^a ^b Silicon Compounds, Silicon Halides. Collins, W.: Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley & Sons, Inc, 2001.
^ "Fluorides (as F)". Immediately Dangerous to Life or Health Concentrations (IDLH). 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. (1953). "Silicon Tetrafluoride". Inorganic Syntheses. Inorganic Syntheses. 4. pp. 145–6. doi:10.1002/9780470132357.ch47. ISBN 9780470132357.CS1 maint: uses authors parameter (link)
^ Hoffman, C. J.; Gutowsky, H. S. (1953). Silicon Tetrafluoride. Inorganic Syntheses. 4. pp. 147–8. doi:10.1002/9780470132357.ch48.CS1 maint: uses authors parameter (link)
^ 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 (3): 249–256. doi:10.1186/BF03353024. S2CID 55173591.
^ Kruszewski, Ł., Fabiańska, M.J., Ciesielczuk, J., Segit, T., Orłowski, R., Motyliński, R., Moszumańska, I., Kusy, D. 2018 – First multi-tool exploration of a gas-condensate-pyrolysate system from the environment of burning coal mine heaps: An in situ FTIR and laboratory GC and PXRD study based on Upper Silesian materials. Science of the Total Environment, 640-641, 1044-1071; DOI: 10.1016/j.scitotenv.2018.05.319

[collins-1] Jump up to: ^a ^b Silicon Compounds, Silicon Halides. Collins, W.: Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley & Sons, Inc, 2001.

[2] "Fluorides (as F)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[3] 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.

[4] Hoffman, C. J.; Gutowsky, H. S. (1953). "Silicon Tetrafluoride". Inorganic Syntheses. Inorganic Syntheses. 4. pp. 145–6. doi:10.1002/9780470132357.ch47. ISBN 9780470132357.CS1 maint: uses authors parameter (link)

[5] Hoffman, C. J.; Gutowsky, H. S. (1953). Silicon Tetrafluoride. Inorganic Syntheses. 4. pp. 147–8. doi:10.1002/9780470132357.ch48.CS1 maint: uses authors parameter (link)

[6] Shimizu, M. "Silicon(IV) Fluoride" Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. doi:10.1002/047084289X.rs011

[7] 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 (3): 249–256. doi:10.1186/BF03353024. S2CID 55173591.

[Kuszewski_et_al._2018-8] Kruszewski, Ł., Fabiańska, M.J., Ciesielczuk, J., Segit, T., Orłowski, R., Motyliński, R., Moszumańska, I., Kusy, D. 2018 – First multi-tool exploration of a gas-condensate-pyrolysate system from the environment of burning coal mine heaps: An in situ FTIR and laboratory GC and PXRD study based on Upper Silesian materials. Science of the Total Environment, 640-641, 1044-1071; DOI: 10.1016/j.scitotenv.2018.05.319

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show v t Silicon compounds
Si(II)	SiO SiS
Si(IV)	SiBr₄ SiC SiCl₄ SiF₄ SiH₄ SiI₄ SiO₂ SiS₂ Si₃N₄

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Names


IUPAC names Tetrafluorosilane Silicon tetrafluoride
Other names Silicon fluoride Fluoro acid air
Identifiers
CAS Number	7783-61-1^Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.029.104
PubChem CID	24556
RTECS number	VW2327000
UNII	K60VCI56YO^Y
UN number	1859
CompTox Dashboard (EPA)	DTXSID0064830
show SMILES F[Si](F)(F)F
Properties
Chemical formula	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	−95.0 °C (−139.0 °F; 178.2 K)^[1]
Boiling point	−90.3 °C (−130.5 °F; 182.8 K)^[1]
Solubility in water	decomposes
Structure
Molecular shape	tetrahedral
Dipole moment	0 D
Hazards
Main hazards	toxic, corrosive
Safety data sheet	ICSC 0576
NFPA 704 (fire diamond)	3 0 2 W
Lethal dose or concentration (LD, LC):
LC_Lo (lowest published)	69,220 mg/m³ (rat, 4 hr)^[2]
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).
Y (what is ^YN ?)
Infobox references