A large collection of various molecular orbital diagram is available in this post. Help yourself in understanding the chemical bonding in molecules through these 101 Diagramss! A molecular orbital diagram is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) molecular orbital method in particular. Molecular orbital diagrams are diagrams of molecular orbital (MO) energy levels, shown as short horizontal lines in the center, flanked by constituent atomic orbital (AO) energy levels for comparison, with the energy levels increasing from the bottom to the top. Take a look at the following example of the molecular orbital diagram.
As you can see in the sample diagram above, there are lines often dashed diagonal lines, connect MO levels with their constituent AO levels. The AO or MO shapes themselves are often not shown on these diagrams. For a diatomic molecule, an MO diagram effectively shows the energetics of the bond between the two atoms, whose AO unbonded energies are shown on the sides. For simple polyatomic molecules with a “central atom” such as methane (CH4) or carbon dioxide (CO2), a MO diagram may show one of the identical bonds to the central atom. The following molecular orbital diagrams contain the chemical bonding of carbon, Co2, and He2.
One of these orbitals is called a bonding molecular orbital because electrons in this orbital spend most of their time in the region directly between the two nuclei. It is called a sigma () molecular orbital because it looks like an s orbital when viewed along the H-H bond. Electrons placed in the other orbital spend most of their time away from the region between the two nuclei. This orbital is therefore an antibonding, or sigma star (*), molecular orbital. Here are the diagrams for hydrogen, nitrogen, and oxygen.
All presented are the examples of molecular orbital diagrams that you can use as your teaching or learning resources. Use these diagrams to guide you on how to outline the basic quantum-mechanical approach to deriving molecular orbitals from atomic orbitals and to describe traits of bonding and anti-bonding molecular orbitals. Other diagram resources are also available in this site!