Bromine pentafluoride

Bromine pentafluoride, BrF5, is an interhalogen compound and a fluoride of bromine. It is a strong fluorination reagent.

Bromine pentafluoride
IUPAC name
Bromine pentafluoride
3D model (JSmol)
ECHA InfoCard 100.029.234
RTECS number
  • EF9350000
Molar mass 174.894 g.mol−1
Appearance Pale yellow liquid
Density 2.466 g/cm3
Melting point −61.30 °C (−78.34 °F; 211.85 K)
Boiling point 40.25 °C (104.45 °F; 313.40 K)
Reacts with water
Square pyramidal
Main hazards reacts violently with water, powerful oxidizer[1]
Safety data sheet See: data page
External MSDS
R/S statement (outdated) R8 R23/24/25 R34
S45 S36/37/39
NFPA 704 (fire diamond)
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
REL (Recommended)
TWA 0.1 ppm (0.7 mg/m3)[1]
IDLH (Immediate danger)
Related compounds
Other anions
Bromine monochloride
Other cations
Chlorine pentafluoride
Iodine pentafluoride
Related compounds
Bromine monofluoride
Bromine trifluoride
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Phase behaviour
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

BrF5 finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of bromine pentafluoride releases O2 for subsequent analysis.[2] It has also been tested as an oxidizer in liquid rocket propellants and is used as a fluorinating agent in the processing of uranium.


Bromine pentafluoride was first prepared in 1931 by the direct reaction of bromine with fluorine.[3] This reaction is suitable for the preparation of large quantities, and is carried out at temperatures over 150 °C (302 °F) with an excess of fluorine:

Br2 + 5 F2 → 2 BrF5

For the preparation of smaller amounts, potassium bromide is used:[3]

KBr + 3 F2 → KF + BrF5

This route yields bromine pentafluoride almost completely free of trifluorides and other impurities.[3]


Bromine pentafluoride reacts violently with water, but when moderated by dilution with acetonitrile, it will form bromic acid and hydrofluoric acid, simple hydrolysis products:[4]

BrF5 + 3 H2O → HBrO3 + 5 HF

It is an extremely effective fluorinating agent, converting most uranium compounds to the hexafluoride at room temperature.


Bromine pentafluoride is severely corrosive to the skin, and its vapors are irritating to the eyes, skin, and mucous membranes. Exposure to 100 ppm for a few minutes is lethal to most experimental animals. Chronic exposure may cause kidney damage and liver failure.[5]

It may spontaneously ignite or explode upon contact with organic materials or metal dust.[5]


  1. NIOSH Pocket Guide to Chemical Hazards. "#0065". National Institute for Occupational Safety and Health (NIOSH).
  2. Clayton, R.; Mayeda, T. K. (1963). "The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis". Geochimica et Cosmochimica Acta. 27 (1): 43–48. Bibcode:1963GeCoA..27...43C. doi:10.1016/0016-7037(63)90071-1.
  3. Hyde, G. A.; Boudakian, M. M. (1968). "Synthesis routes to chlorine and bromine pentafluorides". Inorganic Chemistry. 7 (12): 2648–2649. doi:10.1021/ic50070a039.
  4. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 834. ISBN 978-0-08-037941-8.
  5. Patnaik, Pradyot (2007). A comprehensive guide to the hazardous properties of chemical substances (3rd ed.). Wiley-Interscience. p. 480. ISBN 0-471-71458-5.
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