Boron trifluoride etherate, strictly boron trifluoride diethyl etherate, or boron trifluoride–ether complex, is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula BF₃O(C₂H₅)₂, often abbreviated BF₃OEt₂. It is a colorless liquid, although older samples can appear brown. The compound is used as a source of

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

in many chemical reactions that require a

Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

. The compound features tetrahedral boron coordinated to a diethylether ligand. Many analogues are known, including the methanol complex.

Reactions

Boron trifluoride etherate serves as a source of

according to the equilibrium: :BF₃OEt₂ BF₃ + OEt₂ The BF₃ binds to even weak Lewis bases, inducing reactions of the resulting adducts with nucleophiles.

References

{{Authority control Fluorides Boron compounds Boron halides Acid catalysts