Lewis Theory

• According to Lewis Theory, a Lewis acid is a substance that accepts a lone electron pair
• A substance that donates the lone electron pair is a Lewis base
• In a Lewis acid-base reaction, a coordinate covalent bond is formed between the reacting atoms
• In the reaction between borane (BH3) and phosphine (PH3), a coordinate covalent bond is formed between boron and phosphorus to create the Lewis adduct
• The coordination bond originates from the lone pair donated by phosphorus, resulting in a formal charge of +1 on phosphorus and -1 on boron
• In Lewis acid-base reactions, electrons are always transferred in pairs
• Transition metal reactions to form complex ions can be viewed as Lewis acid-base reactions
• In the formation of the copper-ammonia complex, Cu2+ is the Lewis acid and NH3 is the Lewis base
• Distinguishing features of Lewis acids include having an atom with a reduced octet, being electron-deficient, and/or positively charged
• Lewis bases are electron-rich molecules with electronegative atoms bearing lone pairs, such as O and N