# Why are pi (pi) bonds weaker than sigma (sigma) bonds?

Feb 27, 2014

Pi bonds are weaker than sigma bonds because the side-on overlap of p orbitals is less effective than end-on overlap.

#### Explanation:

In a σ bond, the electrons are in orbitals between the nuclei of the bonding atoms.

Electron density is greatest between the nuclei.

The electrons attract the nuclei and form a σ bond — the strongest type of covalent bond.

In a π bond, the p orbitals overlap side-on.

The overlap is less efficient, because the electron density is off to the sides of the σ bond.

The electrons are not as effective in attracting the two nuclei. Thus, a π bond is weaker than a σ bond.