Carbon oxohalides are a group of chemical compounds that contain only carbon, oxygen and halogen atoms: fluorine, chlorine, bromine and iodine. They include carbonyl halides, COX2, and oxalyl halides, C2X2O2, where X = F, Cl, Br or I. The halogen atoms X do not have to be identical; they differ in mixed oxohalides. Most combinations of halogens exist but carbonyl iodide, COI2, is unknown. The carbon–oxygen bond length in carbonyl halides (1.13–1.17 Å)[1] is shorter than in other carbonyl compounds[2] such as aldehydes and ketones, carboxylic acids, esters and amides (1.20–1.21 Å).[3] They are reactive reagents for halogenation,[1] acylation and dehydration reactions.[4]
| Name | Formula | Melting point / °C | Boiling point / °C | C–O bond length / Å |
|---|---|---|---|---|
| Carbonyl fluoride | COF2 | −114 | −83.1 | 1.174 |
| Carbonyl chloride fluoride | COFCl | −42 | ||
| Carbonyl bromide fluoride | COFBr | −20.6 | ||
| Phosgene | COCl2 | −127.8 | +7.6 | 1.166 |
| Carbonyl iodide fluoride | COFI | −90 | +23.4 | |
| Carbonyl bromide chloride | COClBr | |||
| Carbonyl bromide | COBr2 | +64.5 | 1.13 | |
| Oxalyl fluoride | C2F2O2 | −3 | +26.6 | |
| Oxalyl chloride | C2Cl2O2 | −16 | +63 | |
| Diphosgene | C2Cl4O2 | −57 | +128 | |
| Triphosgene | C3Cl6O3 | +80 | +206 |
See also
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References
edit- ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 304–305. ISBN 978-0-08-037941-8.
- ^ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford University Press. p. 917. ISBN 978-0-19-965763-6.
- ^ David R. Lide, ed. (1995). CRC Handbook of Chemistry and Physics (84th ed.). CRC Press. p. 9-34. ISBN 978-0849304842.
- ^ Smith, Michael B.; March, Jerry (2007). March's Advanced Organic Chemistry (6th ed.). John Wiley & Sons. pp. 724, 728, 1276, 1427, 1550. ISBN 978-0-471-72091-1.