11. A ? * orbital, pi antibonding orbital, will also produce a phase change when rotated about the internuclear axis. 12. The bond order is equal to the number of bonding electrons minus the number of antibonding electrons, divided by 2. 13. The three states only differ in the occupancy and spin states of electrons in the two degenerate ? * antibonding orbitals. 14. The metal donates electrons back from ( a different ) filled d-orbital into the empty ? * antibonding orbital. 15. If the species shifted antarafacially then it would form an antibonding orbital and there would not be a constructive sigma shift. 16. The highest energy, partially filled orbitals are antibonding , and so their filling weakens the bond order from three to two. 17. Sigma bonding has been calculated to show a great antibonding character in the At 2 molecule and is not as favorable energetically. 18. :: The bonding and corresponding antibonding are in the same general area, not really " separated from each other ". 19. Due to conservation of orbital symmetry, the bonding orbital ? AS is forced to correlate with the antibonding orbital ? * AS. 20. :The above sounds good, but I also think that idea of diatomic elements arises from bonding and antibonding of MO theory.
