Chlorotrifluorosilane

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Chlorotrifluorosilane
Chlorotrifluorosilane-2D.png
Names
Preferred IUPAC name
Chlorotri(fluoro)silane
Other names
silicon chlorotrifluoride [1]
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/ClF3Si/c1-5(2,3)4 X mark.svgN
    Key: WOLDFAYTXKMDAQ-UHFFFAOYSA-N Yes check.svgY
  • F[Si](F)(F)Cl
Properties
ClF3Si
Molar mass 120.53371
Appearancecolorless gas
Density 1.31 g/mL
Melting point −138 °C (−216 °F; 135 K)
Boiling point critical point 303.7 K at 3.46 MPa
reacts
Vapor pressure 16600
1.279
Structure
distorted tetrahedron
0.636 D(gas)
Related compounds
Related compounds
 tetrafluorosilane
dichlorodifluorosilane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN (what is  Yes check.svgYX mark.svgN ?)

Chlorotrifluorosilane is an inorganic gaseous compound with formula SiClF3 composed of silicon, fluorine and chlorine. It is a silane that substitutes hydrogen with fluorine and chlorine atoms.

Production

By heating a mixture of anhydrous aluminium chloride and sodium hexafluorosilicate to between 190 and 250 °C a mixture of gases containing chlorotrifluorosilane is given off. These are condensed at -196 °C degrees and fractionally distilled at temperatures up to -78 °C. [2]

SiClF3 can be made by reacting silicon tetrachloride and silicon tetrafluoride gases at 600 °C, producing a mixture of fluorochlorosilanes including about one quarter SiClF3. [3]

SiClF3 can be made by reacting silicon tetrachloride with antimony trifluoride. An antimony pentachloride catalyst assists. The products are distilled to separate it out from tetrafluorosilane and dichlorodifluorosilane. [4] [5] [6]

At high temperatures above 500 °C silicon tetrafluoride can react with phosphorus trichloride to yield some SiClF3. This is unusual because SiF4 is very stable. [7]

Silicon tetrachloride can react with trifluoro(trichloromethyl)silane to yield SiClF3 and CCl3SiCl3. [8]

2-Chloroethyltrifluorosilane or 1,2-dichloroethyltrifluorosilane can be disassociated by an infrared laser to yield SiClF3 and C2H4 (ethylene) or vinyl chloride. By tuning the laser to a vibration frequency of a particular isotope of silicon, different isotopomers can be selectively broken up in order to have a product that only concentrates one isotope of silicon. So silicon-30 can be increased to 80% by using the 934.5 cm−1 line in a CO2 laser. [9]

The first published preparation of SiClF3 by Schumb and Gamble was by exploding hexafluorodisilane in chlorine: Si2F6 + Cl2 → 2SiClF3. Other products of this explosion may include amorphous silicon, SiCl2F2 and SiF4. [10]

Chlorine reacts with silicon tetrafluoride in the presence of aluminium chips at 500-600 °C to make mostly silicon tetra chloride and some SiClF3. [11]

Mercuric chloride when heated with SiF3Co(CO)4 breaks the bond to form a 90% yield of SiClF3. [12]

The combination of SiF4 and chlorodimethylphosphine yields some SiClF3. [13]

Trifluorosilane SiHF3 reacts with gaseous chlorine to yield SiClF3 and HCl. [14]

Properties

Molecular size and angles

Bond length for Si–Cl is 1.996 Å and for Si–F is 1.558 Å. The bond angle ∠FSiCl = 110.2° and ∠FSiF = 108.7°. [4] The bond length between silicon and chlorine is unusually short, indicating a 31% double bond. This can be explained by the more ionic fluoride bonds withdrawing some charge allowing a partial positive charge on the chlorine. [15]

The molecular dipole moment is 0.636  Debye. [4]

Bulk properties

Between 129.18 and 308.83 K the vapour pressure in mm Hg at temperature T in K is given by log10 P = 102.6712 -2541.6/T -43.347 log10 T + 0.071921T -0.000045231 T2. [16]

The heat of formation of chlorotrifluorosilane is -315.0 kcal/mol at 298K. [17]

Reactions

Chlorotrifluorosilane is hydrolysed by water to produce silica.

Chlorotrifluorosilane reacts with trimethylstannane ((CH3)3SnH) at room temperature to make trifluorosilane in about 60 hours. [18]

Use

Proposed uses include a dielectric gas with a high breakdown voltage, and low global warming potential, a precursor for making fluorinated silica soot, and a vapour deposition gas.

Chlorotrifluorosilane can form an addition compound with pyridine with formula SiClF3.2py (py=pyridine) [19] An addition compound with trimethylamine exists. [20] [21] This addition compound is made by mixing trimethylamine vapour with Chlorotrifluorosilane and condensing out a solid at -78 °C. If this was allowed to soak in trimethylamine liquid for over eight hours, a diamine complex formed (2Me3N·SiClF3). [21] At 0° the disassociation pressure of the monoamine complex was 23 mm Hg. [21]

SiClF3− is a trigonal bipyramidal shape with a Cl and F atom on the axis. It is formed when gamma rays hit the neutral molecule. [22]

Chlorotetrafluorosilicate (IV) (SiClF4−) can form a stable a pale yellow crystalline compound tetraethylammonium chlorotetrafluorosilicate. [23]

Related Research Articles

<span class="mw-page-title-main">Silane</span> Chemical compound (SiH4)

Silane (Silicane) is an inorganic compound with chemical formula SiH4. It is a colorless, pyrophoric, toxic gas with a sharp, repulsive, pungent smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Silane with alkyl groups are effective water repellents for mineral surfaces such as concrete and masonry. Silanes with both organic and inorganic attachments are used as coupling agents. They are commonly used to apply coatings to surfaces or as an adhesion promoter.

<span class="mw-page-title-main">Tungsten hexafluoride</span> Chemical compound

Tungsten(VI) fluoride, also known as tungsten hexafluoride, is an inorganic compound with the formula WF6. It is a toxic, corrosive, colorless gas, with a density of about 13 kg/m3 (22 lb/cu yd). It is the only known gaseous transition metal compound and the densest known gas under standard ambient temperature and pressure. WF6 is commonly used by the semiconductor industry to form tungsten films, through the process of chemical vapor deposition. This layer is used in a low-resistivity metallic "interconnect". It is one of seventeen known binary hexafluorides.

In chemistry, an interhalogen compound is a molecule which contains two or more different halogen atoms and no atoms of elements from any other group.

Chlorine trifluoride is an interhalogen compound with the formula ClF3. It is a colorless, poisonous, corrosive, and extremely reactive gas that condenses to a pale-greenish yellow liquid, the form in which it is most often sold. It is famous for its extreme oxidation properties. The compound is primarily of interest in plasmaless cleaning and etching operations in the semiconductor industry, in nuclear reactor fuel processing, historically as a component in rocket fuels, and various other industrial operations owing to its corrosive nature.

<span class="mw-page-title-main">Chlorine pentafluoride</span> Chemical compound

Chlorine pentafluoride is an interhalogen compound with formula ClF5. This colourless gas is a strong oxidant that was once a candidate oxidizer for rockets. The molecule adopts a square pyramidal structure with C4v symmetry, as confirmed by its high-resolution 19F NMR spectrum. It was first synthesized in 1963.

<span class="mw-page-title-main">Chlorine monofluoride</span> Chemical compound

Chlorine monofluoride is a volatile interhalogen compound with the chemical formula ClF. It is a colourless gas at room temperature and is stable even at high temperatures. When cooled to −100 °C, ClF condenses as a pale yellow liquid. Many of its properties are intermediate between its parent halogens, Cl2 and F2.

In inorganic chemistry, chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride.

<span class="mw-page-title-main">Hexafluorosilicic acid</span> Octahedric silicon compound

Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.

<span class="mw-page-title-main">Sulfur tetrafluoride</span> Chemical compound

Sulfur tetrafluoride is a chemical compound with the formula SF4. It is a colorless corrosive gas that releases dangerous hydrogen fluoride gas upon exposure to water or moisture. Sulfur tetrafluoride is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries.

<span class="mw-page-title-main">Selenium tetrafluoride</span> Chemical compound

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

Silicon compounds are compounds containing the element silicon (Si). As a carbon group element, silicon often forms compounds in the +4 oxidation state, though many unusual compounds have been discovered that differ from expectations based on its valence electrons, including the silicides and some silanes. Metal silicides, silicon halides, and similar inorganic compounds can be prepared by directly reacting elemental silicon or silicon dioxide with stable metals or with halogens. Silanes, compounds of silicon and hydrogen, are often used as strong reducing agents, and can be prepared from aluminum–silicon alloys and hydrochloric acid.

In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula AOmXn, where X is a halogen. Known oxohalides have fluorine (F), chlorine (Cl), bromine (Br), and/or iodine (I) in their molecules. The element A may be a main group element, a transition element, a rare earth element or an actinide. The term oxohalide, or oxyhalide, may also refer to minerals and other crystalline substances with the same overall chemical formula, but having an ionic structure.

<span class="mw-page-title-main">Thiophosphoryl fluoride</span> Chemical compound

Thiophosphoryl fluoride is an inorganic molecular gas with formula PSF3 containing phosphorus, sulfur and fluorine. It spontaneously ignites in air and burns with a cool flame. The discoverers were able to have flames around their hands without discomfort, and called it "probably one of the coldest flames known". The gas was discovered in 1888.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

Difluoroamino sulfur pentafluoride is a gaseous chemical compound of fluorine, sulfur, and nitrogen. It is unusual in having a hexa-coordinated sulfur atom with a link to nitrogen. Other names for this substance include difluoro(pentafluorosulfur)amine, pentafluorosulfanyldifluoramine, and pentafluorosulfanyl N,N-difluoramine.

<span class="mw-page-title-main">Difluorosilane</span> Chemical compound

Difluorosilane is a gaseous chemical compound with formula SiH2F2. It can be considered as a derivative of silane with two hydrogen atoms replaced with fluorine.

<span class="mw-page-title-main">Chlorine trifluoride oxide</span> Chemical compound

Chlorine oxide trifluoride or chlorine trifluoride oxide is a corrosive liquid molecular compound with formula ClOF3. It was developed secretly as a rocket fuel oxidiser.

Diphosphorus tetrafluoride is a gaseous compound of phosphorus and fluorine with formula P2F4. Two fluorine atoms are connected to each phosphorus atom, and there is a bond between the two phosphorus atoms. Phosphorus can be considered to have oxidation state +2, as indicated by the name phosphorus difluoride.

<span class="mw-page-title-main">Terbium(IV) fluoride</span> Chemical compound

Terbium(IV) fluoride is an inorganic compound with a chemical formula TbF4. It is a white solid that is a strong oxidizer. It is also a strong fluorinating agent, emitting relatively pure atomic fluorine when heated, rather than the mixture of fluoride vapors emitted from cobalt(III) fluoride or cerium(IV) fluoride.

<span class="mw-page-title-main">2-Chloro-1,1-difluoroethylene</span> Chemical compound

2-Chloro-1,1-difluoroethene (also known as R 1122, u-HCFC-1122 or HCFO-1122) is a toxic unsaturated hydrochlorofluorocarbon which can be written as CF2=CHCl. The HCFO portion of the name stands for hydrochlorofluoroolefin. Another constitutional isomer of it, 1-chloro-1,2-difluoroethylene, is known as HCFO-1122a.

References

  1. ↑ Inorganic Syntheses, Inc (22 September 2009). Inorganic Syntheses. John Wiley & Sons. p. 266. ISBN   9780470132654.{{cite book}}: |first1= has generic name (help)
  2. ↑ Schmeißer, Martin; Jenkner, Herbert (1952). "Notizen: Zur Kenntnis anorganischer Säurefluoride (I)" (PDF). Zeitschrift für Naturforschung. 7 (3): 191–192. doi:10.1515/znb-1952-0310. S2CID   95929863.
  3. ↑ US 2395826,Hill, Julian W.&Lindsey Jr. V, Richard,"Preparation of chlorofluorosilanes",issued 3 May 1946
  4. 1 2 3 Cox, A.P.; Gayton, T.R.; Rego, C.A. (November 1988). "Microwave spectrum, structure, quadrupole coupling constant and dipole moment of chlorotrifluorosilane and iodotrifluorosilane". Journal of Molecular Structure. 190: 419–434. Bibcode:1988JMoSt.190..419C. doi:10.1016/0022-2860(88)80301-6.
  5. ↑ Booth, Harold Simmons; Swinehart, Carl F. (July 1935). "The Fluorochlorosilanes". Journal of the American Chemical Society. 57 (7): 1333–1337. doi:10.1021/ja01310a050.
  6. ↑ Annual Reports on the Progress of Chemistry. 1940. p. 151.
  7. ↑ Suresh, B.S.; Padma, D.K. (September 1985). "Halogen exchange reactions of silicon tetrafluoride with phosphorus trichloride and phosphoryl chloride". Journal of Fluorine Chemistry. 29 (4): 463–466. Bibcode:1985JFluC..29..463S. doi:10.1016/S0022-1139(00)85111-8.
  8. ↑ Weidenbruch, Manfred; Pierrard, Claude (April 1977). "Reaktionen von Halogeniden des Siliciums, Germaniums und Zinns mit Diazomethan und Dichlorcarben- Transfer-Agentien". Chemische Berichte (in German). 110 (4): 1545–1554. doi:10.1002/cber.19771100437.
  9. ↑ Dementyev, Petr S.; Nizovtsev, Anton S.; Chesnokov, Evgenii N. (July 2011). "Infrared photoreaction of 2-chloroethyltrifluorosilane". Journal of Photochemistry and Photobiology A: Chemistry. 222 (1): 77–80. Bibcode:2011JPPA..222...77D. doi:10.1016/j.jphotochem.2011.05.004.
  10. ↑ Schumb, Walter C.; Gamble, E. Lee (October 1932). "Fluorochlorides of Silicon". Journal of the American Chemical Society. 54 (10): 3943–3949. doi:10.1021/ja01349a018.
  11. ↑ Zuckerman, J. J (17 September 2009). Inorganic Reactions and Methods, the Formation of Bonds to Halogens. John Wiley & Sons. p. 361. ISBN   9780470145388.
  12. ↑ Zhou, Yong (3 September 2013). Organosilicon Chemistry: 2: Plenary Lectures Presented at the Second International Symposium on Organosilicon Chemistry. Elsevier. p. 443. ISBN   9781483284828.
  13. ↑ Journal of the Chinese Chemical Society. Chinese Chemical Society. 1999. p. 450. ISBN   9780021926541.
  14. ↑ Gmelin, Leopold (1996). Silicon: Supplement volume. Springer. p. 103. ISBN   9783540937289.
  15. ↑ Pauling, Linus (January 1960). The Nature of the Chemical Bond and the Structure of Molecules and Crystals: An Introduction to Modern Structural Chemistry . Cornell University Press. p.  312. ISBN   0801403332.
  16. ↑ Yaws, Carl L.; Nijhawan, Sachin; Bu, Li (1995). "Appendix C Coefficients for vapor pressure equation". Handbook of Vapor Pressure. Vol. 4. pp. 352–357. doi:10.1016/S1874-8813(06)80008-9. ISBN   9780884153948.
  17. ↑ Gordon, M. S.; Francisco, J. S.; Schlegel, H. B. (1993). "THEORETICAL INVESTIGATIONS OF THE THERMOCHEMISTRY AND THERMAL DECOMPOSITION OF SILANES, HALOSILANES, AND ALKYLSILANES" (PDF). Advances in Silicon Chemistry. 2. JAI Press: 153.
  18. ↑ Gmelin, Leopold (1996). Silicon: Supplement volume. Springer. p. 83. ISBN   9783540937289.
  19. ↑ Hensen, Karl; Wagner, Hans Bernhard (February 1976). "Über einige Verbindungen gemischter Siliciumhalogenide mit Pyridin". Chemische Berichte (in German). 109 (2): 411–414. doi:10.1002/cber.19761090201.
  20. ↑ Sommer, Leo Harry (1965). Stereochemistry, mechanism and silicon: An introduction to the dynamic stereochemistry and reaction mechanisms of silicon centers . McGraw-Hill. pp.  19–20.
  21. 1 2 3 Fergusson, J. E.; Grant, D. K.; Hickford, R. H.; Wilkins, C. J. (1959). "21. Co-ordination of trimethylamine by halides of silicon, germanium, and tin". Journal of the Chemical Society (Resumed): 99–103. doi:10.1039/JR9590000099.
  22. ↑ Hasegawa, Akinori; Uchimura, Schunichiro; Koseki, Kohji; Hayashi, Michiro (January 1978). "ESR spectrum and structure of the SiF3Cl− radical anion". Chemical Physics Letters. 53 (2): 337–340. Bibcode:1978CPL....53..337H. doi:10.1016/0009-2614(78)85410-4.
  23. ↑ Edwards, H.G.M.; Fawcett, V.; Rose, S.J.; Smith, D.N. (May 1992). "The preparation and Raman spectroscopic study of the chlorotetrafluorosilicate (IV) ion, SiF4Cl−". Journal of Molecular Structure. 268 (4): 353–361. Bibcode:1992JMoSt.268..353E. doi:10.1016/0022-2860(92)80222-4.

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