How Do Symmetry and Overlap Determine Molecular Orbital Interactions?

[Juche]

How do you determine the symmetry of the orbitals and whether they overlap in a molecular orbital diagram?

 

[chem_tr]

Well, s orbitals are spherical, so they can overlap with any orbital (s and p, and even d). p orbitals are not spherical, so they only overlap with same face-looking orbital; for example, two p orbitals, after losing one by overlapping with s orbital, have no common symmetry other than themselves; they overlap to give a pi bond.

I know this is hard to tell without a diagram, it tells better than me.

 

[ravenprp]

The symmetry of the orbitals in a molecular orbital diagram can be determined by considering the symmetry of the atomic orbitals that combine to form the molecular orbitals. This can be done by using group theory and applying the principles of symmetry operations, such as rotation and reflection, to the atomic orbitals. The resulting molecular orbitals will have the same symmetry as the atomic orbitals that combine to form them.

To determine whether the orbitals overlap in a molecular orbital diagram, we can use the concept of bonding and antibonding orbitals. If the orbitals have the same symmetry and are in-phase, they will overlap and form a bonding molecular orbital. On the other hand, if the orbitals have opposite symmetries and are out-of-phase, they will overlap and form an antibonding molecular orbital. This can be visualized in a molecular orbital diagram, where the bonding orbitals are lower in energy and the antibonding orbitals are higher in energy.

It is important to note that the degree of orbital overlap also plays a role in determining the strength of the bonding or antibonding interaction. Stronger overlap results in a more stable bonding orbital, while weaker overlap leads to a less stable interaction.

Overall, understanding the symmetry of the orbitals and their overlap in a molecular orbital diagram is crucial in predicting the properties and reactivity of molecules.