In Chapter 10 we looked at the p molecular orbitals
for ethene and 1,3-butadiene (review ?)
Now we will look at the p molecular orbitals
for benzene. With 6 C atoms contributing to the p
system, we need to create 6 molecular orbitals. These are shown below.
The most stable orbital, p1, is the
all in-phase combination. We then have two orbitals, p2
and p3, that are still bonding
but each with one node. There are then two orbitals p4
and p5, that are anti-bonding
each with two nodes. Finally, the least stable orbital, p6,
is the all out-of-phase combination with three nodes.
Once we put the p electrons into these molecular
orbitals, we see that maximum stability is being gained because
all
of the 6 p electrons completely fill
the three bonding orbitals. This is referred to as a closed shell
p-electron configuration.
