Chemistry Reference
In-Depth Information
(a)
C
3
H
2
H
3
H
1
H
6
H
4
H
1
H
3
H
5
H
2
C
1
i
i
H
5
H
4
H
6
H
6
H
2
H
3
H
5
H
4
H
1
(b)
H
1
H
5
iC
1
H
1
H
2
H
4
H
5
H
2
H
6
H
3
H
4
H
3
H
6
Figure 2.6
The compound operation iC
3
for ethane in the staggered conformation: (a) using
flying wedge notation; (b) in the Newman projection.
(a)
S
1
H
6
H
4
H
2
H
1
H
3
H
5
H
3
H
2
H
1
C
2
C
1
C
1
C
1
σ
h
C
1
C
2
C
2
H
6
H
2
H
6
H
3
H
4
H
5
H
1
H
5
H
4
(b)
H
2
H
6
H
2
H
6
H
3
H
6
C
1
σ
h
H
2
H
4
H
5
H
3
H
5
H
3
H
4
H
5
H
1
H
1
H
1
H
4
Figure 2.7
Summary of
the improper
rotation operation for ethane in the staggered
conformation.
The missing symmetry operations for ethane in the staggered conformation are improper
rotations. Ethane has an order 6 improper rotation axis,
S
6
, which is illustrated along with
the
S
6
1
operation, in Figure 2.7. After describing the operations that the
S
6
axis leads to,
we will use them to close the symmetry point group of ethane.
The Newman projection in Figure 2.7b shows the ethane molecule looking directly
down the C
C bond. If all the hydrogen atoms were in the same plane, we would
