Chemistry Reference
In-Depth Information
b
c
a
f
d
e
ψ
1
ψ
2
ψ
3
ψ
4
ψ
5
-1/2
+1
+1
+1
+
-1/2
+
+
-
+
+1
+
ψ
1
+
ψ
1
ψ
1
+
ψ
2
i3
i=3
i1
i=1
-
/
2
-1/2
+1
+1
-
1
/
+
1
+1
0
+1
+1
+1
+1
0
+1
0
-
1
/
-
+
+
-
/
2
+
ψ
3
+
ψ
3
ψ
3
+
ψ
4
ψ
1
+
ψ
3
i=3
i=1
i=2
i=3
i=1
i=2
Figure 9.9 VB canonical structures and Pauling superposition patterns for benzene
.
Resonance between the two Kekule structures
Y ¼ c
1
c
1
þc
2
c
2
ð
9
:
111
Þ
3
2
x
4
þ
3
2
x
þ
¼
0
ð
9
:
112
Þ
x
4
þ
3
2
x
þ
3
2
12
5
5x
2
12x
¼
x
ð
5x
12
Þ¼
0
)
x
¼
0
;
x
¼
ð
9
:
113
Þ
