Bromine pentafluoride

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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
Identifiers
CAS number 7789-30-2
PubChem 24606
ChemSpider 23008 YesY
RTECS number EF9350000
Jmol-3D images Image 1
Properties
Molecular formula BrF5
Molar mass 174.894 g.mol−1
Appearance Pale yellow liquid
Density 2.466 g/cm3
Melting point −61.30 °C
Boiling point 40.25 °C
Solubility in water reacts
Structure
Molecular shape Square pyramidal
Hazards
MSDS External MSDS
R/S statement R8 R23/24/25 R34
S45 S36/37/39
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g., fluorine Special hazard W+OX: Reacts with water in an unusual or dangerous manner AND is oxidizer.NFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions Bromine monochloride
Other cations Chlorine pentafluoride
Iodine pentafluoride
Related compounds Bromine monofluoride
Bromine trifluoride
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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

It melts at −61.30 °C and boils at 40.25 °C. BrF5 finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of bromine pentafluoride releases O2 for subsequent analysis.[1] It is also been tested as an oxidizer in liquid rocket propellants and is used as a fluorinating agent in the processing of uranium.

Preparation[edit]

Bromine pentafluoride was first prepared in 1931 by the direct reaction of bromine with fluorine.[2] 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:[2]

KBr + 3 F2 → KF + BrF5

This route yields bromine pentafluoride almost completely free of trifluorides and other impurities.[2]

Reactions[edit]

Bromine pentafluoride reacts explosively with water, but when moderated by dilution with acetonitrile, it will form bromic acid and hydrofluoric acid, simple hydrolysis products:[3]

BrF5 + 3 H2O → HBrO3 + 5 HF

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

Hazards[edit]

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 nephrosis and hepatosis.[4]

It may spontaneously ignite or explode upon contact with organic materials or metals in powdered form.[4]

References[edit]

  1. ^ 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.  edit
  2. ^ 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.  edit
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 834. ISBN 0080379419. 
  4. ^ 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[edit]