Boron trifuloride is
obtained by the treatment of calcium fluoride with boron trioxide in presence
of conc. sulphuric acid.
It can also be obtained
by treating boron trioxide with carbon and fluorine.
+ 3C + 3F2 → 2BF3
In the laboratory pure
BF3 is prepared by the thermal decomposition of benzene diazonium
Boron trifluoride has a
planar geometry. It is an electron deficient compound and accepts electron
pairs to form coordinate covalent bonds. They form complex of the type [BX4]-.
BF3 + NH3
→ F3 ← B NH3
BF3 + H2O
→ F3B ← OH2
On hydrolysis, boric
acid is obtained. This then gets converted into fluoro boric acid.
Boron trifluoride is used for preparing HBF4, a
catalyst in organic chemistry
It is also used as a fluorinating reagent.