Substituent
The CH₃ group is part of the same molecule.
It is not a methane molecule attached by an intermolecular force.
Molecular compound · aromatic hydrocarbon
Toluene
C₇H₈
Toluene is C₆H₅CH₃, also called methylbenzene. It keeps the aromatic benzene ring but replaces one ring hydrogen with a methyl group.
Identity rule: toluene is not a physical mixture of benzene and methane. The methyl carbon is covalently bonded to the aromatic ring.
Essentials
Toluene is methyl-substituted benzene.
The ring remains aromatic; one hydrogen is replaced by CH₃. This small substitution changes molecular formula, mass and reactivity.
Detail
The source-derived structure fixes the ring–methyl connectivity.
The aromatic ring remains planar, while the methyl group can rotate around the bond connecting it to the ring.
Local motion
Aromaticity does not make the whole molecule rigid.
The ring is planar, but the methyl group can rotate about the ring–CH₃ bond.
Understand
Replacing one benzene H by CH₃ changes properties without destroying aromaticity.
Benzene and toluene share the same aromatic ring framework, but the methyl substituent changes electron distribution and creates new side-chain chemistry.
Compare benzene
Same aromatic core, different compound.
Substitution is one of the main ways organic chemistry builds families of aromatic molecules.
Reference identifiers
Names and identifiers that pin down the chemical identity.
| Formula | C₇H₈ / C₆H₅CH₃ |
|---|---|
| CAS Registry Number | 108-88-3 |
| PubChem CID | 1140 |
Advanced
Push past the first model without losing the simple picture.
Is the methyl carbon part of the aromatic ring?
No. The methyl carbon sits outside the six-membered aromatic ring.
Does toluene retain aromaticity?
Yes. The six-membered ring still contains a delocalized six-π-electron aromatic system.
Why is toluene less water-compatible than phenol?
Toluene lacks phenol's polar O–H group and has no strong hydrogen-bonding site.
Constituent elements