1. Cyclic Hydrocarbons & Aromatic Compounds
SCH3U/4C
Nomenclature & Bonding

2. Cycloalkanes
Many natural and artificial organic compounds contain rings of carbon atoms with distinct chemical and physical properties.
These compounds are known as cycloalkanes.
Cycloalkanes contain:
C-H bonds (single)
C-C single bonds (they are saturated cyclic compounds)

3. Cycloalkanes The general formula for a cycloalkane is CnH2n
Cycloalkanes are often drawn using condensed structure or line structure:
Example: Cyclohexane

4. Naming Cycloalkanes
Determine the length of the parent chain (please note this could be a straight chain parent chain or a cyclic parent chain).
If the parent chain is cyclic:
Name the alkane with the prefix cyclo-
Name the side chains, giving the lowest combination of number for the carbons they are attached to
Example:
Parent chain = hexane
 cyclohexane
Side chains: 1 methyl
1 ethyl
Name:
1-ethyl-3-methylcyclohexane

5. Naming Cycloalkanes
Sometimes the cyclic hydrocarbon can be a side chain of the straight-parent chain.
In this case, we change the ending of the cyclic portion to –yl, to indicate it is a side chain/branch.
Parent chain = 10 C’s  decane
Side chains: 1 methyl group on C6
1 cyclopropyl group on C3
Name: 6-methyl-3-cyclopropyldecane

6. Aromatic Compounds
Aromatic compounds are those that contain a benzene ring.
The benzene ring, C6H6, is a 6-carbon ring containing alternating double bonds

7. Naming Aromatic Compounds with One Side-Chain
When there is only 1 side chain attached to a benzene ring, name the side group, followed by –benzene:
Examples:

8. Naming Aromatic Compounds with Two Side-Chains
When 2 side chains of equal size are attached to a benzene ring, we name according to the pattern of carbons in which the side groups are attached to:

9. Examples: