Organic Fonctions organiques
Each organic function is defined by a specific functional group — the set of atoms that gives the molecule its characteristic chemical behavior. Pick a function below to see the definition, general formula, naming rule, properties, applications and worked examples.
Repérez le motif structural répétitif. C=C indique un alcène ; C≡C, un alcyne ; C=O en bout de chaîne, un aldéhyde ; et C=O entre deux carbones, une cétone. Les hétéroatomes sont également utiles : -OH indique un alcool, -COOH un acide carboxylique, -COO- un ester, -O- un éther, -NH₂ une amine, and -CONH₂ un amide.
Carte comparative
A molecular formula can be shared by different compounds. What defines the function is connectivity: which atoms are bonded, and what type of bond connects them.
| Fonction | Characteristic group | Useful behavior clue | Known example |
|---|---|---|---|
| Alkane | single C–C | nonpolar and relatively unreactive | propane |
| Alkene | C=C | addition and polymerization | ethene |
| Alkyne | C≡C | linear geometry and addition | ethyne |
| Alcohol | R–OH | hydrogen bonding | ethanol |
| Aldehyde | R–CHO | terminal carbonyl and easy oxidation | ethanal |
| Ketone | R–CO–R' | internal carbonyl and solvent behavior | propanone |
| Carboxylic acid | R–COOH | acidity and hydrogen-bonded dimers | ethanoic acid |
| Ester | R–COO–R' | hydrolysis and characteristic aromas | ethyl ethanoate |
| Ether | R–O–R' | accepts, but does not donate, H | ethoxyethane |
| Amine | R–NH₂ / R₂NH / R₃N | basicity and protonation | methanamine |
| Amide | R–CONH₂ | resonance and peptide bonds | ethanamide |
| Halide | R–X | substitution and elimination | chloromethane |
Pourquoi la fonction compte
Le groupe fonctionnel modifie la polarité, le point ebullition, la solubilité, l acidité, la basicité et la réactivité. That is why ethanol and ethyl ethanoate, even though both contain carbon, hydrogen, and oxygen, differ greatly in odor, miscibility, and reactions.
- Identify the functional group in the structure.
- Compare its polarity and intermolecular interactions.
- Learn the suffix when it is principal and prefixes when it is not.
- Test a structure in the simulator and inspect the name breakdown.
Ordre de priorité (IUPAC)
When a molecule has more than one functional group, only one becomes the suffix (the "main group") — the others become prefixes. The priority order, from highest to lowest, is:
- Carboxylic acids
- Esters
- Amides
- Nitriles
- Aldehydes
- Ketones
- Alcohols / Phenols
- Amines
- Ethers
Sulfonic acids and acyl halides are also important acid derivatives. Simple halides are always prefixes, never suffixes. See the full detail in nomenclature IUPAC.
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