Molecular Theory 8

1
Fred J. Grieman
Molecular Theory (8) Localized bonding via hybrid
orbitals Examples on board Molecular Orbital
Theory Delocalized p MOs Combine Localized
for s Delocalized for p
2
Polyatomic molecules and Delocalized
Bonding Valence Bond works well for
localized ? and ? bonding
not so well for delocalized bonding
(resonance structures) Molecular Orbital Theory
is excellent for delocalized ? bonding Our
method combine VB for ? bonding, MO for ?
bonding NO3- as an example
N hybridization? sp2 O hybridization?
sp2
p-bonding delocalized p N(2p) OA(2p) OB(2p)
OC(2p)
sNO N(sp2) O(sp2) (3 of these)
3
Conjugation alternating double bonds 1,3
butadiene
4 carbons
2 double bonds in the 1 3 postions
4 p orbitals 4 p orbitals Notice of nodes
w/r/t energy
Blackboard
4
Benzene
Resonance Structures delocalized p bonding
Localized ? bonding
Delocalized ? bonding