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Bromine pentafluoride

Bromine pentafluoride
Structure and dimensions of the bromine pentafluoride molecule in the gas phase
Ball-and-stick model of bromine pentafluoride
Space-filling model of bromine pentafluoride
Names
IUPAC name
Bromine pentafluoride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.234
EC Number
  • 232-157-8
RTECS number
  • EF9350000
UNII
UN number 1745
Properties
BrF5
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
Structure
Square pyramidal
Hazards
Main hazards Reacts violently with water, powerful oxidizer[1]
Safety data sheet See: data page
External MSDS
GHS pictograms GHS03: OxidizingGHS05: CorrosiveGHS06: ToxicGHS08: Health hazard
GHS Signal word Danger
H271, H305, H314, H318, H330, H370, H371, H373
P210, P220, P221, P260, P264, P270, P271, P280, P283, P284, P301+310, P301+330+331, P303+361+353, P304+340, P305+351+338, P306+360, P307+311, P309+311, P310, P314, P320, P321, P331, P363, P370+378
NFPA 704 (fire diamond)
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
none[1]
REL (Recommended)
TWA 0.1 ppm (0.7 mg/m3)[1]
IDLH (Immediate danger)
N.D.[1]
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.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references

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

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.

Preparation

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]

Reactions

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

BrF5 + 3 H2O → HBrO3 + 5 HF

It is an extremely effective fluorinating agent, being able to convert most uranium compounds to uranium hexafluoride at room temperature.

Hazards

Bromine pentafluoride is severely corrosive to the skin, and its vapors are irritating to the eyes, skin, and mucous membranes. In moist air, it will in fact release "smoke" containing hydrofluoric acid vapors coming from its reaction with the water in the air. Additionally, exposure to 100 ppm or more for more than one minute 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]

References

  1. ^ a b c d 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. ^ a b c 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. ^ a b Patnaik, Pradyot (2007). A comprehensive guide to the hazardous properties of chemical substances (3rd ed.). Wiley-Interscience. p. 480. ISBN 0-471-71458-5.

External links