Why are amines Lewis bases?
Lewis' theory of bases and acids says that:
- Acids are lone pair acceptors
- Bases are lone pair donors.
A base doesn't lose its lone pair, but shares it, like a dative covalent bond.
An amine has a nitrogen atom connected to three alkyl groups, while also having a lone pair of electrons:
These lone pair of electrons can bond to another molecule by filling a space in an empty orbital.