Trichlorosilane

Trichlorosilane

Names
IUPAC name trichlorosilane
Other names silyl trichloride, silicochloroform
Identifiers
CAS Number	10025-78-2 Y
3D model (JSmol)	Interactive image
ChemSpider	23196 Y
ECHA InfoCard	100.030.026
EC Number	233-042-5
PubChem CID	24811
RTECS number	VV5950000
UNII	QZY2645L6V Y
UN number	1295
CompTox Dashboard (EPA)	DTXSID4029301
InChI InChI=1S/Cl3HSi/c1-4(2)3/h4H Y Key: ZDHXKXAHOVTTAH-UHFFFAOYSA-N Y InChI=1/Cl3HSi/c1-4(2)3/h4H Key: ZDHXKXAHOVTTAH-UHFFFAOYAH
SMILES Cl[SiH](Cl)Cl
Properties
Chemical 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[1]
Safety data sheet (SDS)	ICSC 0591
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H224, H250, H302, H314, H332
Precautionary statements	P231, P280, P305+P351+P338+P310, P310, P370+P378
NFPA 704 (fire diamond)	3 4 2 W
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 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).
N  (what is YN ?)
Infobox references

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 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.^[2]

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 (the blue diamond means "Dangerous when wet")

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]

References[]

• Semiconductors: Silicon: Substrate Manufacture: Polycrystalline silicon Production