Covalent bond in oxygen atom

Oxygen atoms have six electrons in their valence shell and need to share more to fill their outer shell. Each oxygen atom shares two electrons with the other oxygen atom, forming a double bond. 

The two covalent bonds in an oxygen molecule are one sigma bond and one pi bond. The sigma bond is formed by the axial overlap of the oxygen atoms’ 2p atomic orbitals, and the pi bond is formed by the lateral overlap of the oxygen atoms’ 2p atomic orbitals. 

Covalent bonds are stronger and more common than ionic bonds in living organisms. 

Covalent bonds form when two atoms share a pair of valence electrons, and the shared electrons are attracted to both atoms’ nu