# Between pi bond and sigma bond, which bond can be broken easily and why?

Oct 2, 2014

$\pi$ bonds can easily be broken. Why?

$\sigma$ bond
$\sigma$ bonds are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals.

By this definition, common forms of sigma bonds are s+s, pz+pz, s+pz and dz2+dz2.

$\pi$ bond
$\pi$ bonds are usually weaker than sigma bonds ; the C-C double bond has a bond energy less than twice the C-C single bond bond energy!
From the perspective of quantum mechanics, this bond's weakness is explained by significantly less overlap between the component p-orbitals due to their parallel orientation.