Tetrasilane
Chemical compound
From Wikipedia, the free encyclopedia
Tetrasilane is a silane with the structure formula SiH3–(SiH2)2–SiH3. It is the silane analog of butane.
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| Names | |
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| IUPAC name
Tetrasilane | |
| Other names
n-Tetrasilane | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.132.456 |
| EC Number |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| H10Si4 | |
| Molar mass | 122.420 g·mol−1 |
| Appearance | colourless liquid that self ignite in air[1] |
| Density | 0.792 g·cm−3[2] |
| Melting point | −89.9 °C[2] |
| Boiling point | 108.1 °C[2] |
| reacts[1] | |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H250 | |
| Related compounds | |
Related compounds |
butane |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Tetrasilane can be prepared by reacting magnesium silicide (Mg2Si) with acids like 20% phosphoric acid in 50–60 °C.[3]
- Mg2Si + 4 H+ → SinH2n+2
The reaction can produce silanes up to n=15. The reaction of magnesium silicide with 25% hydrochloric acid produces 40% monosilane, 30% disilane, 15% trisilane, 10% tetrasilane and 5% higher silanes.[4] The mixture can be separated by fractional distillation.
In addition, higher silanes can also be obtained by discharges monosilane:[3]
- SiH4 → SiH2 + H2
- SiH2 + SiH4 → H3Si−SiH3
- SiH2 + H3Si−SiH3 → H3Si−SiH2−SiH3
- SiH2 + H3Si−SiH2−SiH3 → H3Si−SiH2−SiH2−SiH3
Properties
Tetrasilane is a colourless, pyrophoric liquid that has a disgusting odour. Even below 54 °C, it will still spontaneously combust.[1] It is even more unstable than trisilane, slowly decomposing at room temperature, releasing hydrogen and forming shorter chain silanes.[5]
Reactions
Photochemical disproportionation of tetrasilane will produce 3-silylpentasilane and disilane.[6]
- 2 Si4H10 → Si2H6 + H3Si−SiH(Si2H6)2
With the presence of aluminium chloride, heating tetrasilane in xylene will allow isomerization to isotetrasilane.[7]
- 2 H3Si−SiH2−SiH2−SiH3 → H3Si−SiH(SiH3)2