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Ok, I'm learning about molecular orbital (MO) theory, and I'm confused about what a nonbonding orbital is. My book says it is an MO with the same energy as an atomic orbital (AO), but since the MO is the sum of two AOs I'm wondering, which AO it is equal to in energy?

Is it equal to one of the AOs, or the sum of both without any reduction in energy?
sweatdrop

Thanks for the reply!

I think that's what you're supposed to do for figuring out the bonds!

I found out the answer to my question a little later...

If you are describing the atomic orbitals mathematically with a wave equation (which is probably a lot more confusing, and I'm still not very clear about it...) I think then you take a linear combination of the atomic orbital equations to get the equation for the molecular orbital. So from 2 atomic orbitals you get two molecular orbitals (I'm not sure why ...This is pretty abstract, but I'm guessing it makes sense mathematically.) For the bond to happen the energy of the bonding orbital should be less than the energy of the individual atomic orbitals.

My confusion was that I thought the equation for the energy of the molecular orbital was also a direct sum of the equations for the energies of atomic orbitals. But it's not, it's the equation describing the MOs that is the sum or linear combination of the wave equations describing the AOs. And the AOs used are supposed to be similar in energy so the non-bonding orbital would have the same energy as both of them.

xd Yeah... *head hurts* Chem and physics at the same time are a lot, there are so many rules to understand for both.