3.1: Stability of Conjugated Dienes- Molecular Orbital Theory 3.2: Electrophilic Additions to Conjugated Dienes- Allylic Carbocations 3.3: Kinetic vs. Thermodynamic Control of Reactions 3.4: Naming Aromatic Compounds 3.5: Structure and Stability of Benzene 3.6: Aromaticity and the Hückel 4n + 2 Rule In 1931, German chemist and physicist Erich Hückel proposed a theory to help determine if a planar ring molecule would have aromatic properties. His rule states that if a cyclic, planar molecule has 4n+2 π electrons, it is considered aromatic. This rule would come to be known as Hückel's Rule. 3.7: Aromatic Ions Carbanions and carbocations may also show aromatic stabilization. 3.8: Aromatic Heterocycles- Pyridine and Pyrrole 3.9: Polycyclic Aromatic Compounds 3.10: Spectroscopy of Aromatic Compounds 3.S: Benzene and Aromaticity (Summary)