Octafluorocyclobutane, or perfluorocyclobutane, C4F8, is an organofluorine compound which enjoys several niche applications. Octafluorocyclobutane is a colourless gas and shipped as a liquefied gas. It is the perfluorinated analogue of cyclobutane whereby all C–H bonds are replaced with C–F bonds.
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| Names | |||
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| Preferred IUPAC name
Octafluorocyclobutane | |||
| Other names
Freon-C-318, perfluorocyclobutane | |||
| Identifiers | |||
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3D model (JSmol) |
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| 1909266 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.003.705 
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| EC Number |
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| E number | E946 (glazing agents, ...) | ||
| 131113 | |||
PubChem CID |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| C4F8 | |||
| Molar mass | 200.03 g/mol | ||
| Appearance | colourless gas | ||
| Density | 1.637 g/cm3 at −5.8 °C (liquid)
9.97 kg/m3 at −6 °C and 1 atm (gas) | ||
| Melting point | −40.1 °C (−40.2 °F; 233.1 K) | ||
| Boiling point | −5.8 °C (21.6 °F; 267.3 K) | ||
| 0.016 vol/vol (1.013 bar and 20 °C) | |||
| Viscosity | 109e-6 Poise (1.013 bar and 0 °C) | ||
| Hazards | |||
| GHS labelling: | |||
 
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| Warning | |||
| H280, H411 | |||
| P273, P391, P410+P403, P501 | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Octafluorocyclobutane is produced by the dimerization of tetrafluoroethylene and the reductive coupling of 1,2-dichloro-1,1,2,2-tetrafluoroethane.[1]
In the production of semiconductor materials and devices, octafluorocyclobutane serves as a deposition gas and etchant.[2] It has also been investigated as a refrigerant in specialised applications, as a replacement for ozone depleting chlorofluorocarbon refrigerants. Exploiting its volatility and chemical inertness, octafluorocyclobutane may be found in some aerosolized foods. It is listed by the Codex Alimentarius under number 946 (E946 for EU). It is investigated as a possible replacement for sulfur hexafluoride as a dielectric gas.
Its critical point is at 115.3 °C and 2.79 MPa.
