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### Sigma and Pi order in MO

Posted: Sun Nov 13, 2016 9:57 pm
What order are you supposed to put the sigma and pi bonds when doing the molecular orbital theory? In some cases in the 2p orbitals, the sigma bond is lower in energy than the pi bonds and the opposite in other cases. I think there was a rule about switching between the two once you hit the 8th charge? I'm really confused about this.

### Re: Sigma and Pi order in MO

Posted: Mon Nov 14, 2016 12:40 am
Correct me if I'm wrong but I think $\pi$2p bond switches with the $\sigma$2p once z$\geq$8 because there are actually electrons occupying the space for pi bonds.