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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Lewis acid

An electron-pair acceptor: a species that takes a lone pair from a Lewis base to form a new bond. Electron-deficient atoms such as B in BFX3\ce{BF3} and cations such as HX+\ce{H+} are Lewis acids.

BFFF
B in BFX3\ce{BF3} has only 6 electrons and an empty orbital to accept a pair.

Example

AlClX3+ClX−→AlClX4X−\ce{AlCl3 + Cl- -> AlCl4-}: aluminium accepts a lone pair from chloride and reaches an octet.

See alsoLewis baseIncomplete octetLone pair