140
Coplanar side-overlap
of 6 atomic p orbitals
H
.c. s c
I
,€„
H
77 molecular orbital
with 3 electrons above
plane and 3 below
Top view
(bottom view the same)
FIGURE 9-29
The 77- molecular orbital of C 6 H 6 .
C-C—C—C
Plane
of atoms
bond
Side view
central N atom to provide a p orbital for side-overlap for both the O and the
other N, it will be necessary for it to use sp digonal orbitals. The sp orbitals will
be used to make cr bonds, while the two remaining/? orbitals will merge to make
TT bonds.
The NO 2 molecule illustrates what must be done with a single unpaired
electron on the central atom [see predictive rule #2(c), p 119]. It must occupy a
molecular orbital but, unlike the usual situation, the orbital won't be filled. In
/ N
Angular
0
: N = N = o:
Linear
?
P
Angular
Cl
Tetrahedral
/
\
H
H
Coplanar
H
H
Tetrahedral about each C
FIGURE 9-30
Examples of molecules with various bond characteristics.