Trichlorosilane

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Trichlorosilane
Trichlorosilane-2D-stereo.png
Trichlorosilane-3D-vdW.png Trichlorosilane-3D-balls.png
Identifiers
CAS number 10025-78-2 YesY
PubChem 24811
ChemSpider 23196 YesY
EC number 233-042-5
UN number 1295
RTECS number VV5950000
Jmol-3D images Image 1
Properties
Molecular formula HCl3Si
Molar mass 135.45 g/mol
Appearance colourless 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)
Solubility in water hydrolysis
Hazards
MSDS ICSC 0591
EU Index 014-001-00-9
EU classification Highly flammable (F+)
Harmful (Xn)
Corrosive (C)
R-phrases R12, R14, R17, R20/22, R29, R35
S-phrases (S2), S7/9, S16, S26, S36/37/39, S43, S45
NFPA 704
Flammability code 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., propane Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazard W: Reacts with water in an unusual or dangerous manner. E.g., cesium, sodiumNFPA 704 four-colored diamond
Flash point −27 °C (−17 °F; 246 K)
Autoignition temperature 185 °C (365 °F; 458 K)
Explosive limits 1.2–90.5%
Related compounds
Related chlorosilanes Chlorosilane
Dichlorosilane
Dichloromethylsilane
Chlorodimethylsilane
Silicon tetrachloride
Related compounds Trifluorosilane
Tribromosilane
Chloroform
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Trichlorosilane is an inorganic compound with the formula HSiCl3. 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 silicone 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.[1]

Production[edit]

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

Si + 3 HCl → HSiCl3 + H2

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

Tank car of trichlorosilane (the blue diamond means "Dangerous when wet").

It is also produced from silicon tetrachloride:[2]

Si + 3 SiCl4 + 2 H2 → 4 HSiCl3

Applications[edit]

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

HSiCl3 → Si + HCl + Cl2

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 perfluordecyltrichlorosilane (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 an injection molding tools.[3]

References[edit]

  1. ^ Lianhong Xu, Ravi Kurukulasuriya, "Trichlorosilane" Encyclopedia of Reagents for Organic Synthesis, 2006. doi:10.1002/047084289X.rt213.pub2
  2. ^ Simmler, W. (2005), "Silicon Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a24_001 
  3. ^ Cech J, Taboryski R (2012). "Stability of FDTS monolayer coating on aluminum injection molding tools". Applied Surface Science 259: 538–541. doi:10.1016/j.apsusc.2012.07.078. 

External links[edit]