Cycloalkanes

Add the prefix cyclo– before the parent chain name.

Structure	Name
3-carbon ring	cyclopropane
4-carbon ring	cyclobutane
5-carbon ring	cyclopentane
6-carbon ring	cyclohexane

For substituted cycloalkanes, number the ring to give substituents the lowest locants. If one substituent is present, it is at C-1 (no locant needed).

Benzene

Benzene is named as its own parent. Monosubstituted benzenes are named as benzene derivatives (e.g., chlorobenzene, nitrobenzene). For disubstituted benzenes, three arrangements are possible:

• ortho (o–) — substituents at positions 1 and 2
• meta (m–) — substituents at positions 1 and 3
• para (p–) — substituents at positions 1 and 4

The ortho/meta/para prefix system is widely used alongside IUPAC locants.

When benzene is a substituent rather than the parent, it is named phenyl–.

---