Register to reply

Question about molecular orbital theory

by reyrey389
Tags: molecular, orbital, theory
Share this thread:
reyrey389
#1
Apr11-12, 04:19 PM
P: 11
I know that the sigma 2p bonding orbital could be less/higher in energy than the pi 2p bonding (based on if it is C2,N2,B2 etc), but

Why is the sigma 2p antibonding orbital always higher in energy than the pi 2p antibonding one?
Phys.Org News Partner Chemistry news on Phys.org
New molecule puts scientists a step closer to understanding hydrogen storage
Chemists develop new formulation for the generation of green flames
Four billion-year-old chemistry in cells today
DrDu
#2
Apr12-12, 03:35 AM
Sci Advisor
P: 3,555
When you neglect in a first step the s orbitals, the sigma bonding p orbital would be below the pi bonding p orbitals. However, in the second step the sigma bonding p orbital mixes with the sigma bonding s orbitals which shifts them up in energy. Also the antibonding p orbital can be shifted up by that mechanism, although the effect is weaker due to their larger energetic separation and it would not change the ordering of the orbitals.


Register to reply

Related Discussions
A question on Molecular Orbital theory Chemistry 2
Molecular orbital theory of heterodiatomics? Biology, Chemistry & Other Homework 1
Difference between Valence bond theory and molecular orbital theory? Chemistry 4
Molecular Orbital Theory Biology, Chemistry & Other Homework 2
Molecular Orbital Theory Chemistry 2