The molecule does not exist.
The bond order of O2 is 2 and that of N2 is 3 so that N2 is more stable and less reactive than O2.
The bond energy of O2, molecule is 494 KJ mole-1 whereas that of N2 molecule is 945 (KJ) mol-1. \O2 is more reactive than N2.
Bond Energy
[Bond energy is the quantity of energy which is released when the bond is formed. It is also equal to the bond disssociation — energy, which is the quantity of energy required to break the bond and generate the gaseous atoms]
When the number of antibonding electrons increases, the bond order is decreased and stability also is decreased. Removal of antibonding electrons increases the stability of the resulting species as it has a higher bond order.
Addition of electrons to the bonding M.O. increases the bond order as also the stability of the molecule. Removal of electrons from the bonding M.O. has the opposite effect.
O2+ is more stable than O2
M.O. picture of O2 is sIs2 *sIs2 s2s2 *s2s2 s2px2 P2 Py2 = P 2Pz2 *P2Py1 and *P2P2z
b. o. = 2 for O2
For O2+ an electron is removed from the antibonding *P2P orbital. Thus order increases by 0.5
O2+ sIs2 *sIs2 s2s2 *s2s2 s2px2 P2 Py2 P 2Pz2 *P2Py1
b.o. = 25
Unlike the V.B. method, the M.O. Theory explains the observed paramagnetism of molecular oxygen.
The M.O. picture shows two unpaired electrons in the antibonding *P2py and *P2pzorbitals, which accounts for the magnetic behaviour.
In fact, O2 behaves as a diradical. .*•
The bond length and the bond order are inversely related. When bond order increases bond length decreases and vice versa.