Naming comes down to spotting the highest-priority group and giving it the suffix. Everything else in the molecule becomes a prefix.
| Functional group | Structure | IUPAC suffix | Prefix | Example |
|---|---|---|---|---|
| Alkane | R–H | -ane | alkyl- | Ethane |
| Alkene | C=C | -ene | alkenyl- | Ethene |
| Alkyne | C≡C | -yne | alkynyl- | Ethyne |
| Arene | Ar–H | -benzene | phenyl- / aryl- | Benzene |
| Haloalkane | R–X | — | halo- | Chloroethane |
| Alcohol | R–OH | -ol | hydroxy- | Ethanol |
| Ether | R–O–R′ | — | alkoxy- | Diethyl ether |
| Thiol | R–SH | -thiol | sulfanyl- | Ethanethiol |
| Amine | R–NH2 | -amine | amino- | Methylamine |
| Aldehyde | R–CHO | -al | oxo- / formyl- | Ethanal |
| Ketone | R–CO–R′ | -one | oxo- | Propanone |
| Carboxylic acid | R–COOH | -oic acid | carboxy- | Ethanoic acid |
| Ester | R–COO–R′ | -oate | alkoxycarbonyl- | Ethyl ethanoate |
| Amide | R–CONH2 | -amide | carbamoyl- | Ethanamide |
| Acyl halide | R–COX | -oyl halide | halocarbonyl- | Ethanoyl chloride |
| Anhydride | RCO–O–COR′ | -oic anhydride | — | Ethanoic anhydride |
| Nitrile | R–C≡N | -nitrile | cyano- | Ethanenitrile |
| Nitro | R–NO2 | — | nitro- | Nitromethane |
R and R′ stand for any carbon chain; X is a halogen; Ar is an aromatic ring. The suffix is used when the group is the highest-priority one in the molecule, the prefix when it is not.