Learn more about molecular orbital diagram of oxygen (O2) to know the chemical bonding of oxygen. This kind of diagram is used as to qualitatively explain the chemical bonding in molecules in terms of a molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) molecular orbital method in particular. Check out the first O2 molecular orbital diagram below.
These MO diagrams can explain why some molecules exist and others do not. In the O2 molecular orbital diagram, when creating the molecular orbitals from the p orbitals, notice the three atomic orbitals split into three molecular orbitals, a singly degenerate σ and a doubly degenerate π orbital. Another property we can observe by examining molecular orbital diagrams is the magnetic property of diamagnetic or paramagnetic. If all the electrons are paired, there is a slight repulsion and it is classified as diamagnetic. If unpaired electrons are present, it is attracted to a magnetic field, and therefore paramagnetic.
Oxygen is an example of a paramagnetic diatomic. Notice the bond order of diatomic oxygen is two. MO treatment of dioxygen is different from that of the previous diatomic molecules because the pσ MO is now lower in energy than the 2π orbitals. This is attributed to an interaction between the 2s MO and the 2pz MO. Distributing 8 electrons over 6 molecular orbitals leaves the final two electrons as a degenerate pair in the 2pπ* antibonding orbitals resulting in a bond order of 2.
The molecular orbital theory describes the distribution of electrons in molecules in much the same way that the distribution of electrons in atoms is described using atomic orbitals. The diagrams given above show the oxygen molecular orbital which will help you in understanding the chemical bonding of oxygen. Check back soon for more educational diagrams!