Dimethylsilane

Structural formula
General
Surname	Dimethylsilane
other names	Dimethylsilyl dihydride 2-silapropane
Molecular formula	C 2 H 8 Si
Brief description	colorless gas with a disgusting, sweet smell
External identifiers / databases
CAS number 1111-74-6 EC number 214-184-7 ECHA InfoCard 100,012,895 PubChem 66185 Wikidata Q16322551
properties
Molar mass	60.17 g mol −1
Physical state	gaseous
density	2.73 kg m −3 (at 0 ° C and 1013 mbar) 0.591 kg m −3 (at 1.0 bar and 15 ° C) 0.611 g cm −3 (at boiling point) 0.68 g · cm -3 (at -80 ° C)
Melting point	−150.2 ° C
boiling point	−19.6 ° C
Vapor pressure	3.8 bar (20 ° C) 5.1 bar (30 ° C) 8.4 bar (50 ° C)
solubility	hydrolyzed in water
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 220-280 P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dimethylsilane is a chemical compound from the group of organosilicon compounds .

Extraction and presentation

Dimethylsilane can be produced in quantitative yield by reacting dichlorosilane with an excess of gaseous dimethylzinc .

${\displaystyle \mathrm {SiCl_{2}H_{2}+\ 2\ Zn(CH_{3})_{2}\ {\xrightarrow[{}]{}}\ Si(CH_{3})_{2}H_{2}\ +\ 2\ ClZnCH_{3}} }$

It can also be obtained by reducing dichlorodimethylsilane with a suitable reducing agent (e.g. lithium aluminum hydride ).

properties

Dimethylsilane is an extremely flammable, colorless gas with a flash point ≤ −30 ° C and an ignition temperature of 205 ° C. It is heavier than air ( relative gas density = 2.11), forms explosive mixtures with air (lower explosion limit at 1.2 vol.% Or 30 g · m ^-3 , upper explosion limit at 74 vol.% Or 1851 g · m ^-3 ) and can self-ignite when exposed to air.

It hydrolyzes in water or acids to form dimethylsilanediol and hydrogen, which often ignites immediately. When the liquid flows out or when large amounts of gas escape, cold mists form and spread across the floor.

use

As a precursor molecule, dimethylsilane can be used as a silicon source for the deposition of silicon-containing layers by means of chemical vapor deposition (CVD) , which are required in the manufacture of products in the electronics and photovoltaic industry, e.g. B. for low-k dielectrics .

Related links

• Methylsilane
• Trimethylsilane
• Tetramethylsilane

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n} Entry for CAS no. 1111-74-6 in the GESTIS substance database of the IFA , accessed on July 2, 2018(JavaScript required) .
2. ^ 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 .
3. ↑ Air Liquide Gas Encyclopedia: Dimethylsilane ( Memento of July 8, 2012 in the Internet Archive )
4. ↑ Qingguo Wu, Karen K. Gleason: Plasma-enhanced chemical vapor deposition of low-k dielectric films using methylsilane, dimethylsilane, and trimethylsilane precursors . In: Journal of Vacuum Science & Technology A . tape 21 , no. 2 , March 2003, p. 388-393 , doi : 10.1116 / 1.1539086 .