Lewis was successful in including acid and bases that catalyze organic reactions without
proton or hydroxyl ions.
Lewis Acid: A substance that accepts an electron pair.
Lewis base: A substance that donates an electron pair.
E.g. BF3(g)
+ :NH3(g) ® F3B:NH3(s)
Lewis Acid Lewis base Lewis acid/base adduct
the Lewis base donates a pair of electrons to the acid forming a coordinate covalent bond common to coordination compounds. Lewis
acids/bases will be discussed later in describing reaction mechanism