Here’s the difference between sigma (σ) and pi (π) bonds:
- Sigma (σ) bond:
- Formed by head-on overlap of orbitals.
- Stronger than pi bond.
- Found in single bonds.
- Allows rotation around the bond.
- Pi (π) bond:
- Formed by side-to-side overlap of orbitals.
- Weaker than sigma bond.
- Found in double and triple bonds (one π for double, two π for triple).
- Does not allow rotation around the bond.
Example:
- C–C → 1 sigma bond
- C=C → 1 sigma + 1 pi bond
- C≡C → 1 sigma + 2 pi bonds
In short:
Sigma = head-on, strong, rotatable.
Pi = side-on, weaker, no rotation.