Alkenes and alkynes

Organic Reactions Memory Game

This is a game to practice all Organic Chemistry reactions.  This specific example is only for the reactions that are covered in the 1st semester of the 2-semester Organic sequence.  Basically, there are 3 piles of cards face-down on the table:  Reactants, Reagents, and Products.  The student draw a card each from 2 piles (either Reactant - Reagent, Reactant - Product, or Reagent - Product).  The student then looks at the two cards drawn and has to provide the missing element (if the reaction is possible, of course). I haven't shown all cards, otherwise the file would have become too big to

Why is 1,4-cyclohexadiene stable?

Daniel J. Berger
Author Affiliation: 
Bluffton University

Why is 1,4-cyclohexadiene stabilized? Using qualitative perturbation theory to teach conjugation


Six-carbon polyenes display quite regular properties, when one compares their stabilities using hydrogenation enthalpies. Each double bond in a conjugated system is worth about 10 kJ/mol in resonance energy, and non-conjugated dienes show no resonance energy. Cyclohexadienes are puzzling: 1,3-cyclohexadiene is less stable, and 1,4-cyclohexadiene is more stable, than corresponding open-chain dienes. Qualitative molecular orbital perturbation theory can be used to explain these anomalies.