Phosphorus pentabromide: Difference between revisions
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| IUPACName = Phosphorus pentabromide |
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| OtherNames = Tetrabromophosphonium bromide |
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Revision as of 09:14, 12 June 2022
Names | |
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IUPAC name
Phosphorus pentabromide
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Other names
Tetrabromophosphonium bromide
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.029.260 |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
PBr5 | |
Molar mass | 430.49 g/mol |
Appearance | yellow solid |
Density | 3.61 g/cm3 |
Melting point | ca. 100 °C (decomposes) |
Boiling point | 106 °C (223 °F; 379 K) (decomposes) |
decomposes | |
Solubility | decomposes in ethanol soluble in CCl4 and CS2 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Phosphorus pentabromide is a reactive, yellow solid of formula PBr5, which has the structure PBr4+ Br− in the solid state but in the vapor phase is completely dissociated to PBr3 and Br2. Rapid cooling of this phase to 15 K leads to formation of the ionic species phosphorus heptabromide ([PBr4]+[Br3]−).[1]
It can be used in organic chemistry to convert carboxylic acids to acyl bromides. It is highly corrosive. It decomposes above 100 °C to give phosphorus tribromide and bromine:[2]
Reversing this equilibrium to generate PBr5 by addition of Br2 to PBr3 is difficult in practice because the product is susceptible to further addition to yield phosphorus heptabromide (PBr7).[3]
References
- ^ Corbridge, D. E. C. (2013). Phosphorus: Chemistry, Biochemistry and Technology, Sixth Edition. CRC Press. p. 154. ISBN 978-1-4398-4088-7.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Popov, A. I.; Skelly, N. E. (1954). "Spectrophotometric Study of Phosphorus Pentabromide in Various Solvents". J. Am. Chem. Soc. 76 (15): 3916–3919. doi:10.1021/ja01644a014.