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The Kekulé structure for benzene
In 1865, Kekulé suggested that the carbon atoms of benzene are in a ring, as they are
bonded to each other by alternating single and double bonds, and there’s one
hydrogen atom attached to each carbon atom.
He proposed that benzene was not a single compound, but a mixture of two
compounds in rapid equilibrium.
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It was then proved that structures I and II don’t represent two separate molecules in
equilibrium as keküle had proposed but they are resonating structures.
Benzene is a hybrid of structures I and II.
The hybrid structure is represented by a circle.
Molecular orbital explanation of benzene structure
Benzene is planar six membered ring.
➢ All carbon atoms are sp2 hybridized.
➢ Bond angles are all 120°.
➢ P-Orbitals are parallel to each other and overlap equally all
around the ring resulting in a cloud of electrons above and
below the plane of the ring.
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