Trichlorosilane

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Trichlorosilane
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Names
IUPAC name
trichlorosilane
Other names
silyl trichloride, silicochloroform
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.026 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-042-5
PubChem CID
RTECS number
  • VV5950000
UNII
UN number 1295
  • InChI=1S/Cl3HSi/c1-4(2)3/h4H Yes check.svgY
    Key: ZDHXKXAHOVTTAH-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/Cl3HSi/c1-4(2)3/h4H
    Key: ZDHXKXAHOVTTAH-UHFFFAOYAH
  • Cl[SiH](Cl)Cl
Properties
HCl3Si
Molar mass 135.45 g/mol
Appearancecolourless liquid
Density 1.342 g/cm3
Melting point −126.6 °C (−195.9 °F; 146.6 K)
Boiling point 31.8 °C (89.2 °F; 304.9 K)
hydrolysis
Hazards [1]
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-exclam.svg
Danger
H224, H250, H302, H314, H332
P231, P280, P305+P351+P338+P310, P310, P370+P378
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 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
4
2
W
Flash point −27 °C (−17 °F; 246 K)
185 °C (365 °F; 458 K)
Explosive limits 1.2–90.5%
Safety data sheet (SDS) ICSC 0591
Related compounds
Related chlorosilanes
Chlorosilane
Dichlorosilane
Dichloromethylsilane
Chlorodimethylsilane
Silicon tetrachloride
Related compounds
Trifluorosilane
Tribromosilane
Chloroform
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Trichlorosilane is an inorganic compound with the formula HCl3Si. It is a colourless, volatile liquid. Purified trichlorosilane is the principal precursor to ultrapure silicon in the semiconductor industry. In water, it rapidly decomposes to produce a siloxane polymer while giving off hydrochloric acid. Because of its reactivity and wide availability, it is frequently used in the synthesis of silicon-containing organic compounds. [2]

Contents

Production

Trichlorosilane is produced by treating powdered metallurgical grade silicon with blowing hydrogen chloride at 300 °C. Hydrogen is also produced, as described in the chemical equation:

Si + 3 HCl → HCl3Si + H2

Yields of 80-90% can be achieved. The main byproducts are silicon tetrachloride (chemical formula SiCl4), hexachlorodisilane (Si2Cl6) and dichlorosilane (H2SiCl2), from which trichlorosilane can be separated by distillation.

Tank car of trichlorosilane. UN number: 2988 (Chlorosilanes). ADR hazard identification number: X338 (Highly flammable liquid, corrosive, which reacts dangerously with water) Trichlorsilan-RID.JPG
Tank car of trichlorosilane. UN number: 2988 (Chlorosilanes). ADR hazard identification number: X338 (Highly flammable liquid, corrosive, which reacts dangerously with water)

It is also produced from silicon tetrachloride: [3]

Si + 3 SiCl4 + 2 H2 → 4 HCl3Si

Applications

Trichlorosilane is the basic ingredient used in the production of purified polysilicon.

HCl3Si → Si + HCl + Cl2

Ingredient in hydrosilylation

Via hydrosilylation, trichlorosilane is a precursor to other useful organosilicon compounds:

RCH=CH2 + HSiCl3 → RCH2CH2SiCl3

Some useful products of this or similar reactions include octadecyltrichlorosilane (OTS), perfluoroctyltrichlorosilane (PFOTCS), and perfluorodecyltrichlorosilane (FDTS). These reagents used in surface science and nanotechnology to form Self-assembled monolayers. Such layers containing fluorine decrease surface energy and reduce sticking. This effect is usually exploited as coating for MEMS and microfabricated stamps for a nanoimprint lithography (NIL) and in injection molding tools. [4]

Organic synthesis

Trichlorosilane is a reagent in the conversion of benzoic acids to toluene derivatives. In the first step of a two-pot reaction, the carboxylic acid is first converted to the trichlosilylbenzyl compound. In the second step, the benzylic silyl derivative is converted to the toluene derivative with base. [5]

Safety

Trichlorosilane is highly reactive, and may respond violently (even explosively) to many compounds. [6] This also includes water, potentially producing silicon dioxide, chlorine, hydrogen, hydrogen chloride, and heat. Trichlorosilane can also react with moisture in the air, producing hydrochloric acid. [6] Spills of trichlorosilane may be neutralized using a 1-1 ratio of sodium hydroxide, or a 2-1 ratio of sodium bicarbonate to trichlorosilane. [7] Fires can be extinguished using alcohol-resistant aqueous film-forming foam (AR-AFFF). [6] [7]

Related Research Articles

Silane (Silicane) is an inorganic compound with chemical formula SiH4. It is a colourless, 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. Silanes are commonly used to apply coatings to surfaces or as an adhesion promoter.

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

Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colorless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. It is a part of the chlorosilane family.

Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agent. It is used as a water cleaner and as an etchant for metals.

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

Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2. It forms hydrates. Zinc chloride, anhydrous and its hydrates are colorless or white crystalline solids, and are highly soluble in water. Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride. This salt is hygroscopic and even deliquescent. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O.

<span class="mw-page-title-main">Titanium tetrachloride</span> Inorganic chemical compound

Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4" due to the phonetic resemblance of its molecular formula to the word.

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

Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.

<span class="mw-page-title-main">Iron(II) chloride</span> Chemical compound

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions.

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">Trimethylsilyl chloride</span> Chemical compound

Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.

<span class="mw-page-title-main">Chromium(II) chloride</span> Chemical compound

Chromium(II) chloride describes inorganic compounds with the formula CrCl2(H2O)n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily dissolves in water to give bright blue air-sensitive solutions of the tetrahydrate Cr(H2O)4Cl2. Chromium(II) chloride has no commercial uses but is used on a laboratory-scale for the synthesis of other chromium complexes.

Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.

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

Arsenic trichloride is an inorganic compound with the formula AsCl3, also known as arsenous chloride or butter of arsenic. This poisonous oil is colourless, although impure samples may appear yellow. It is an intermediate in the manufacture of organoarsenic compounds.

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

Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl4. This brown solid features platinum in the 4+ oxidation state.

Hydrosilanes are tetravalent silicon compounds containing one or more Si-H bond. The parent hydrosilane is silane (SiH4). Commonly, hydrosilane refers to organosilicon derivatives. Examples include phenylsilane (PhSiH3) and triethoxysilane ((C2H5O)3SiH). Polymers and oligomers terminated with hydrosilanes are resins that are used to make useful materials like caulks.

Dimethyldichlorosilane is a tetrahedral, organosilicon compound with the formula Si(CH3)2Cl2. At room temperature it is a colorless liquid that readily reacts with water to form both linear and cyclic Si-O chains. Dimethyldichlorosilane is made on an industrial scale as the principal precursor to dimethylsilicone and polysilane compounds.

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

Methyltrichlorosilane, also known as trichloromethylsilane, is a monomer and organosilicon compound with the formula CH3SiCl3. It is a colorless liquid with a sharp odor similar to that of hydrochloric acid. As methyltrichlorosilane is a reactive compound, it is mainly used a precursor for forming various cross-linked siloxane polymers.

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

Chloroauric acid is an inorganic compound with the chemical formula H[AuCl4]. It forms hydrates H[AuCl4nH2O. Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar [AuCl4] anion. Often chloroauric acid is handled as a solution, such as those obtained by dissolution of gold in aqua regia. These solutions can be converted to other gold complexes or reduced to metallic gold or gold nanoparticles.

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

Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2. SeCl4 is used in the synthesis of other selenium compounds.

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

Germanium dichloride is a chemical compound of germanium and chlorine with the formula GeCl2. It is a yellow solid. Germanium dichloride is an example of a compound featuring germanium in the +2 oxidation state.

References

  1. "GESTIS-Stoffdatenbank". gestis.dguv.de.
  2. Lianhong Xu, Ravi Kurukulasuriya, "Trichlorosilane" Encyclopedia of Reagents for Organic Synthesis, 2006. doi : 10.1002/047084289X.rt213.pub2
  3. Simmler, W. "Silicon Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_001.
  4. Cech J, Taboryski R (2012). "Stability of FDTS monolayer coating on aluminum injection molding tools". Applied Surface Science. 259: 538–541. Bibcode:2012ApSS..259..538C. doi:10.1016/j.apsusc.2012.07.078.
  5. George S. Li, David F. Ehler, R. A. Benkeser "Methyl Groups By Reduction Of Aromatic Carboxylic Acids With Trichlorosilane - Tri-n-propylamine: 2-methylbiphenyl" Org. Synth. 1977, volume 56, pp. 83. doi : 10.15227/orgsyn.056.0083
  6. 1 2 3 Trichlorosilane: Safety Data Sheet P-4823 (PDF) (Report). Linde Inc. February 3, 2022. Archived from the original (PDF) on June 6, 2022.
  7. 1 2 Hazardous Substance Fact Sheet: Trichlorosilane (PDF) (Report). New jersey department of health. October 2010.