Bromine trifluoride

Bromine trifluoride

Structural formula, showing bond lengths and angles
Bromine Trifluoride
Identifiers
CAS Number	7787-71-5 N
PubChem	24594
Properties
Chemical formula	BrF3
Molar mass	136.90 g/mol
Appearance	straw-coloured liquid hygroscopic
Odor	Choking, pungent
Density	2.803 g/cm3
Melting point	8.77 °C (47.79 °F; 281.92 K)
Boiling point	125.72 °C (258.30 °F; 398.87 K)
Solubility in water	decomposes violently
Solubility in sulfuric acid	very soluble
Structure
Molecular shape	T-shaped (C2v)
Dipole moment	1.19 D
Vapor pressure	{{{value}}}
Related compounds
Other anions	Bromine monochloride
Other cations	Chlorine trifluoride Iodine trifluoride
Related compounds	Bromine monofluoride Bromine pentafluoride
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
N verify (what is YN ?)
Infobox references

Bromine trifluoride is an interhalogen compound with the formula BrF₃. It is a straw-coloured liquid with a pungent odor. It is soluble in sulfuric acid but explodes on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride (UF₆) in the processing and reprocessing of nuclear fuel.

Synthesis

Bromine trifluoride was first described by Paul Lebeau in 1906, who obtained the material by the reaction of bromine with fluorine at 20 °C:

Br₂ + 3 F₂ → 2 BrF₃

The disproportionation of bromine monofluoride also gives bromine trifluoride:

3 BrF → BrF₃ + Br₂

Structure

Like ClF₃ and IF₃, the BrF₃ molecule is T-shaped. In the VSEPR formalism, the bromine center is assigned two electron pairs. The distance from the bromine each axial fluorine is 1.81 Å and to the equatorial fluorine is 1.72 Å. The angle between an axial fluorine and the equatorial fluorine is slightly smaller than 90° — the 86.2° angle observed is due to the repulsion generated by the electron pairs being greater than that of the Br-F bonds.

Chemical properties

BrF₃ is a fluorinating agent, but less reactive than ClF₃. The liquid is conducting, owing to autoionisation:

2 BrF₃ ⇌ BrF₂⁺ + BrF₄⁻

Many ionic fluorides dissolve readily in BrF₃ forming fluoroanions:

KF + BrF₃ → KBrF₄

External links

• WebBook page for BrF3