Disilane

Disilane

Names
IUPAC name Disilane
Identifiers
CAS Number	1590-87-0 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30597 Y
ChemSpider	66736 Y
ECHA InfoCard	100.014.970
Gmelin Reference	368
PubChem CID	74123
UNII	L4684339WI Y
CompTox Dashboard (EPA)	DTXSID40166558
InChI InChI=1S/H6Si2/c1-2/h1-2H3 Y Key: PZPGRFITIJYNEJ-UHFFFAOYSA-N Y InChI=1/H6Si2/c1-2/h1-2H3 Key: PZPGRFITIJYNEJ-UHFFFAOYAQ
SMILES [SiH3][SiH3]
Properties
Chemical formula	Si2H6
Molar mass	62.218 g·mol−1
Appearance	Colourless gas
Density	2.7 g dm−3
Melting point	−132 °C (−206 °F; 141 K)
Boiling point	−14 °C (7 °F; 259 K)
Solubility in water	Reacts[1]
Vapor pressure	2940.2±0.0 mmHg at 25°C[2]
Conjugate acid	Disilanium
Structure
Dipole moment	0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Extremely flammable
Related compounds
Related disilanes	Hexamethyldisilane
Related compounds	Ethane Digermane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Disilane is a chemical compound with chemical formula Si₂H₆ that was identified in 1902 by Henri Moissan and Samuel Smiles (1877–1953). Moissan and Smiles reported disilane as being among the products formed by the action of dilute acids on metal silicides. Although these reactions had been previously investigated by Friedrich Woehler and Heinrich Buff between 1857 and 1858, Moissan and Smiles were the first to explicitly identify disilane. They referred to disilane as silicoethane. Higher members of the homologous series Si_nH_2n+2 formed in these reactions were subsequently identified by Carl Somiesky (sometimes spelled "Karl Somieski") and Alfred Stock.

At standard temperature and pressure, disilane is a colourless, acrid gas. Disilane and ethane have similar structures, although disilane is much more reactive. Other compounds of the general formula Si₂X₆ (X = hydrogen, halogen, alkyl, aryl, and mixtures of these groups) are called disilanes. Disilane is a group 14 hydride.

Synthesis

Disilane is usually prepared by the hydrolysis of magnesium silicide. This reaction produces silane, disilane, and even trisilane. The method has been abandoned for the production of silane, but it remains viable for generating disilane.^[3] The presence of traces of disilane is responsible for the spontaneous flammability of silane produced by hydrolysis by this method (analogously diphosphine is often the spontaneously pyrophoric contaminant in samples of phosphine).

It also arises by thermal decomposition disilane via both photochemical^[4] and thermal decomposition of silane.

The reduction of Si₂Cl₆ with lithium aluminium hydride affords disilane in modest yield.^[5]

Applications and reactions

Disilane and silane thermally decompose around 640 °C, depositing amorphous silicon. This chemical vapor deposition process is relevant to the manufacture of photovoltaic devices.^[3] Specifically it is utilized in the production of silicon wafers.^[6]

More generally, diorganosilanes are produced by reductive coupling of silyl chlorides, e.g.

2 (CH₃)₃SiCl + 2 Na → (CH₃)₃Si−Si(CH₃)₃ + 2 NaCl

Disilane gas can be used to control pressure of Si vapors during process of graphene growth by thermal decomposition of SiC. Pressure of Si vapors influences quality of produced graphene.^[7]

References