Unformatted text preview: + 3H2 —’ m/Wégjil Predicted: AH°= -360 kJ/mo!
Observed. AH°- - —208 lemol
The observed value iM ess!! This energy difference is the stabilization of benzene. Cepyrighx Q The Meat raw Hi it C: rrpanies Inc. Permission required for repmduelion or disﬁay, commonly referred to as the resonance stabilization (or resonance energy) of benzene All aroma
compounds have large resonance sta 1 zation. : 1 An imaginary molecule,
cyclohexaniene benzene Fig. 112/ pg 429
Modern theories of the structure of benzene: 1. Resonance Explanation: (read ch 11.3)
Let's reconsider Kekulé's 1,2-dibromobenzene structures. -E wumﬁff @WQ% .1
31:: SEE: a 0M? vesmm semi: 3% The only difference between these two structures is the position of the electrons. Thu
are resonance forms, and neither one by itself correctly describes the bonding in the ,m, molecule The resonance hybrid would be an average of the two resonance structures
Analogous, for benzene the two 2 resonance forms are: tie ...
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- Summer '08
- Organic chemistry