Dichlorosilane

Structural formula
General
Surname	Dichlorosilane
other names	DCS
Molecular formula	SiH 2 Cl 2
Brief description	extremely flammable, colorless gas with a pungent odor
External identifiers / databases
CAS number 4109-96-0 EC number 223-888-3 ECHA InfoCard 100,021,717 PubChem 61330 Wikidata Q418556
properties
Molar mass	101.01 g mol −1
Physical state	gaseous
density	1.261 g l −1 (density at boiling point) 4.34 kg m −3 (gaseous at 15 ° C, 1.013 bar)
Melting point	−122.0 ° C
boiling point	8.4 ° C
Vapor pressure	1.666 bar (20 ° C)
solubility	Hydrolysis in water
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 330-220-314-280 EUH: 071 P: 260-280-210-304 + 340-303 + 361 + 353-305 + 351 + 338-315-377-381-405-403
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dichlorosilane is a chemical compound from the group of chlorinated silanes .

Extraction and presentation

Dichlorosilane can be prepared by chlorination of monosilane with hydrogen chloride in the presence of aluminum chloride as catalyst at elevated temperature.

${\displaystyle \mathrm {SiH_{4}+\ 2\ HCl\ {\xrightarrow[{AlCl_{3}}]{100\,{}^{\circ }C,30h}}\ SiH_{2}Cl_{2}\ +\ 2\ H_{2}} }$

In addition, it can be obtained by disproportionation of trichlorosilane over suitable catalysts .

properties

Dichlorosilane is an extremely flammable, corrosive gas that liquefies under pressure. It forms a hydrogen chloride mist on contact with moist air . In water it hydrolyzes to form hydrogen chloride and a mixture of polymeric siloxanes . From a temperature of 55 ° C the compound decomposes, producing hydrogen chloride and, in small amounts, hydrogen and chlorine . There is a risk of self-ignition. The explosion range is between 2.5% by volume (105 g / m ³ ) as the lower explosion limit (LEL) and 80.0% by volume (3359 g / m ³ ) as the upper explosion limit (UEL). It is sensitive to oxygen and UV light . The compound has a critical temperature of 176.3 ° C, a critical pressure of 43.78 bar, a critical density of 0.479 kg / l and a triple point temperature of −122 ° C (melting temperature). The heat of vaporization is 249 kJ / kg.

use

Dichlorosilane is used in semiconductor production for chemical vapor deposition or epitaxy, also mixed with ammonia for the production of silicon nitride or silicon dioxide .

safety instructions

The vapors of dichlorosilane can form an explosive mixture with air ( flash point −28 ° C, ignition temperature 185 ° C).

Web links

• Ansyco: IR spectrum of dichlorosilane

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on dichlorosilane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
2. ↑ ^{a b} Airliquide: Dichlorosilane N30
3. ^ Alfred Stock, Carl Somieski: Siliciumwasserstoffe VI .: Chlorination and methylation of the monosilane . In: Reports of the German Chemical Society (A and B Series) . tape 52 , no. 4 , April 12, 1919, p. 695 , doi : 10.1002 / cber.19190520410 .
4. ↑ Free Patent Online: Method for preparation of dichlorosilane
5. ^ E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
6. ↑ Data sheet dichlorosilane ( Memento from May 18, 2015 in the Internet Archive ) at Messer Schweiz AG (PDF; 207 kB).