Bonding vs Antibonding

[Ashley Van Belle 2B]

I understand how to write the Molecular Orbital diagrams and how to include the bonding and antibonding orbitals. However, I don't completely understand what it means for an orbital to be bonding or antibonding. What is the difference?

[Jenny_Thompson_3I]

The difference between bonding and antibonding is determined from whether or not the molecular orbital is in phase or out of phase. In phase will produce bonding while out of phase will produce antibonding. The phase is determined from the molecular wave function that is a linear combination of two atomic wave functions.

[Cobie_Allen_1H]

I had the same question. This is very helpful! Thank you so much!

[Tatum_Bernat_1E]

Another way to look at it is to look at bonding in terms of waves, because the particles are moving so quickly it's more of a region of probability. You can think of it in the sense of constructive and destructive interference. Two areas where the electron has a high probability of occurring creates a positive interference and can be thought of as constructive probability for where the electron is. Antibonding is the opposite with two regions of somewhat negative probability. Electrons are less likely to be here. These can occur at places like nodes where it is so unlikely, the probability is basically 0. The electrons have a lower energy potential when bonding, because they are more predictable and thus more stable than when the electrons are antibonding.