TTinkerwise
Unlock all
chemistry / Organic Chemistry / free

Aromatic Chemistry

Map the shared electrons that give aromatic rings their unusual stability.

Follow the cause1 / 3

p orbitals connect around a ring. A cyclic, planar, conjugated framework gives π electrons a continuous path.

delocalized electronsbenzene · aromatic
Focus the idea
Aromatic rings share π electrons around a cyclebenzene is a 6-membered ring with 6 π electrons, which the Hückel rule classifies as aromatic. A neutral substituent directs substitution no strong preference.6 π e⁻ = 4(1) + 2 · aromaticRneutraldirects no strong preferenceelectron density
π electrons6
ring state (Hückel)aromatic
substituentneutral
stabilitydelocalized

benzene is planar, cyclic, and fully conjugated with 6 π electrons, a 4n + 2 count (n = 1), so the π electrons delocalize around the ring and it is aromatic.

Hückel's rule applies to planar, cyclic, fully conjugated rings: 4n + 2 π electrons is aromatic, 4n is antiaromatic. Directing effects are for electrophilic aromatic substitution; halogens are the classic exception (deactivating yet ortho/para) and are not modelled.

04 / PRACTICE

Make the chemistry yours.

0 / 3 checked

Answer from the model, then use the explanation to connect the particle picture to the chemical rule.

CHECK 1 / 3

What must be true before using Hückel's rule?