hannoe

Thanks for your replies! Obviously I had mixed some concepts up so I went over them again and it's more clear now. I got the answer that I was looking for (thanks studiot!) - my question was about whether the resonance structures are just changing between each other very quickly or it is actually an average of the resonances. As I understand now the second one is correct. Meaning actually new orbitals form (or the orbitals take a significantly different shape) that have lower energy than the usual molecular orbitals.

Have I understood correctly that the resonance hybrid orbital does not represent any actual orbital (with new shape) in the molecule? If a new orbital would form then only two electrons could be there but there are many examples where different pair of electrons can go an occupy the same orbital in different resonance structures (e.g. conductive polymers could not function otherwise). Moreover if one huge hybrid orbital would form then it could be very big which leads to larger energy level for electrons as more nodes must form, which means higher frequency which mean higher energy... Meaning, the electron pairs that can move around can be only in pi-bonds and AO-s just like in resonance structures. But the energy difference between these orbitals is very small so the electrons can move very fast between them. As a result the molecule cannot be though of as one resonance structure but the combination of many. Is this correct?