Bromine trifluoride
Bromine trifluoride is a highly toxic and corrosive fluoride of bromine with chemical formula BrF3. It was discovered by Paul Lebeau in 1906.[1] It occurs as a colorless, yellow, or gray fuming liquid with an irritating odor. It is soluble in sulfuric acid but may explode on contact with water. While it is a potent fluorinating agent it is less reactive than ClF3. It is used to produce uranium hexafluoride, UF6 in the processing and reprocessing of nuclear fuel.[2]
Synthesis
Bromine trifluoride can be obtained by the reaction of bromine with fluorine at 20 °C.
- Br2 + 3F2 → 2BrF3
The disproportionation of bromine monofluoride is also a source for bromine trifluoride.
- 3BrF → BrF3 + Br2[3]
Structure
Like ClF3 and IF3 the BrF3 molecule is T-shaped. With the two electron pairs the coordination number is 5. 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.[4][5]
Chemistry and Properties
Liquid BrF3 is conducting and this is attributed to dissociation:[2]
- BrF3 ⇌ BrF2+ + BrF4−
Many ionic fluorides dissolve readily in BrF3 forming solvobases[2] e.g.
- KF + BrF3 → KBrF4
References
- ^ Lebeau P. (1906). "The effect of fluorine on chloride and on bromine". Annales de Chimie et de Physique. 9: 241–263.
- ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Simons JH (1950). "Bromine (III) Fluoride - Bromine Trifluoride". Inorganic Synthesis. 3: 184–186.
- ^ Gutmann V (1950). "Die Chemie in Bromtrifuoride". Angewante Chemie. 62: 312–315.
- ^ Meinert H (1967). "Interhalogenverbindungen". Zeitschrift für Chemie. 7: 41.