Question 22.1: Draw structures for the isomers of C5H12.
Draw structures for the isomers of C_{5}H_{12}.
STRATEGY
1. Start by writing all five-carbon atoms in a straight chain. Call this structure isomer (I).
2. Write a four-carbon chain structure bonding the fifth carbon atom to one of the C atoms in the straight chain.
Note that bonding the fifth C atom to either end of the straight chain gives you isomer (I). You have to attach the C atom next to the terminal atom (on either end).
3. Write a three-carbon chain. Do not attach the remaining two carbon atoms as a chain to either end of the three carbon chain. You will get Isomer (I). Attaching one carbon atom to each end of the three-carbon chain also gives you isomer (I).
| isomer (I) five-C chain: -\overset{|}{\underset{|}{C}} -\overset{|}{\underset{|}{C}}-\overset{|}{\underset{|}{C}}-\overset{|}{\underset{|}{C}}-\overset{|}{\underset{|}{C}}-
isomer (II) four-C chain: -\overset{|}{\underset{|}{C}}-\overset{|}{\underset{\underset{|}{-C-} }{\underset{|}{C} } } -\overset{|}{\underset{|}{C}}-\overset{|}{\underset{|}{C}}- Remember, these molecules are three dimensional. isomer (III) three-C chain: -\overset{|}{\underset{|}{C}}-\overset{\overset{\overset{|}{-C-} }{|} }{\underset{\underset{\underset{|}{-C-} }{|} }{C}}-\overset{|}{\underset{|}{C}}- |
Isomer (I)
Isomer (II)
Isomer (III) |