Trisilane is the
silane
Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Sila ...
with the formula H
2Si(SiH
3)
2. A liquid at standard temperature and pressure, it is a silicon analogue of
propane. The contrast with propane however trisilane ignites spontaneously in air.
Synthesis
Trisilane was characterized by
Alfred Stock
Alfred Stock (July 16, 1876 – August 12, 1946) was a German inorganic chemist. He did pioneering research on the hydrides of boron and silicon, coordination chemistry, mercury, and mercury poisoning. The German Chemical Society's Alfred-Stoc ...
having prepared it by the reaction of
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
and
magnesium silicide
Magnesium silicide, Mg2Si, is an inorganic compound consisting of magnesium and silicon. As-grown Mg2Si usually forms black crystals; they are semiconductors with n-type conductivity and have potential applications in thermoelectric generators.
C ...
. This reaction had been explored as early as 1857 by
Friedrich Woehler and Heinrich Buff, and further investigated by
Henri Moissan
Ferdinand Frédéric Henri Moissan (28 September 1852 – 20 February 1907) was a French chemist and pharmacist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. Moissan was one of the original mem ...
and Samuel Smiles in 1902.
[
]
Decomposition
The key property of trisilane is its thermal lability. It degrades to silicon films and SiH4 according to this idealized equation:
:Si3H8 → Si + 2 SiH4
In terms of mechanism, this decomposition proceeds by a 1,2 hydrogen shift that produces disilanes, normal and isotetrasilanes, and normal and isopentasilanes.
Because it readily decomposes to leave films of Si, trisilane has been explored a means to apply thin layers of silicon for semiconductors and similar applications. Similarly, thermolysis
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ...
of trisilane gives silicon nanowires.
References
{{Hydrides by group
Silanes
Inorganic compounds