Which of the following is paramagnetic?

Why O⁻² is Paramagnetic?

Bond order:

• It is the quantity of atoms’ bonds with one another.
• The stable bonding electrons help to increase the bond order.
• Due to the antibonding electrons’ instability, the bond order is being reduced.

Bond order is given by:

• ½ (no. of bonding – no. of anti bonding electrons
• For filling up of electrons, we need to follow the series: σ1s σ1s* σ2s σ2s * σ2pz π2py
• = π2px π2py * = π2px * σ2pz *
• For molecules till nitrogen, there is a slight change in the M.O energy order: σ1s σ1s* σ2s σ2s π2py= π2px * σ2pz π2py = π2px * σ2pz *
• For CO, we see that there are no unpaired electrons and the molecule is thus diamagnetic.
• O^2– molecule, the electronic configuration is: σ1s 2σ1s*2 σ2s 2σ2s *2 σ2pz 2π2py 2π2px 2π2py *2π2px *1

• There are seven antibonding electrons and seven bonding electrons, including one unpaired antibonding orbital electron.
• It is paramagnetic in nature due to the unpaired electron.

The M.O of NO⁺ is as follows:

• From the M.O diagram of NO+, we see that there are no unpaired electrons and the molecule is thus diamagnetic.
• If we construct the M.O diagram of CN, we will see that there are no unpaired electrons.

Therefore, O⁻² is paramagnetic.

Summary:

Which of the following is paramagnetic? (a) CN (b) CO (c) O−2 (d) NO+

From the following, O⁻² is paramagnetic. The elements are small-scale sensitive to magnetic fields and are attracted by the magnetic field. Pragmatic materials that are somewhat attracted by the magnetic fields.