Boron trifluoride is the chemical compound with the formula BF3. This pungent colourless toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds.

Formula: BF3
Molar mass: 67.82 g/mol
Boiling point: -148.5°F (-100.3°C)
Density: 2.76 kg/m³
Melting point: -196.2°F (-126.8°C)