Example of PCl3 acting as both Lewis acid and Lewis base:
Phosphorus trichloride (PCl3) as a Lewis acid:
- In the presence of a molecule like NH3, which has a lone pair of electrons on the nitrogen atom, PCl3 can act as a Lewis acid by accepting a lone pair of electrons from the ammonia molecule.
- The phosphorus atom in PCl3 is electron deficient and can accept an electron pair to complete its octet, making it act as a Lewis acid in this reaction.
- The reaction can be represented as: PCl3 + NH3 → PCl3NH3
Phosphorus trichloride (PCl3) as a Lewis base:
- PCl3 can also act as a Lewis base in the presence of a molecule like BF3, which is electron deficient and can accept an electron pair.
- In this case, the chlorine atoms in PCl3 can donate their lone pairs of electrons to the boron atom in BF3, which is electron deficient and acts as a Lewis acid.
- The reaction can be represented as: PCl3 + BF3 → PCl3BF3
Explanation:
- In the examples provided, PCl3 demonstrates its ability to act as both a Lewis acid and a Lewis base depending on the nature of the reactant molecules it interacts with.
- As a Lewis acid, PCl3 accepts electron pairs to complete its octet, while as a Lewis base, it donates electron pairs to molecules that are electron deficient.
- This dual behavior of PCl3 showcases its versatility in forming coordination complexes with various molecules, highlighting its importance in chemical reactions involving Lewis acids and bases.