Nitronium tetrafluoroborate is an
inorganic compound with formula NO
2BF
4. It is a salt of
nitronium cation and
tetrafluoroborate anion. It is a colorless crystalline solid, which reacts with water to form the corrosive acids
HF and
HNO3. As such, it must be handled under water-free conditions. It is sparsely soluble in many organic solvents.