Key Points emerging from Hückel-Heilbronner theory

• These conclusions are derived for a cycle bounded entirely in 2D space, and for a band of zero width and height!
• For a 4n electron system, a Möbius Cycle is closed shell
  
• A closed shell 4n Möbius cycle has the same π resonance energy as the equivalent (open shell) untwisted Hückel cycle. It is not especially stable!
• For a 4n+2 electron system, a Möbius Cycle is open shell (triplet)
• A open shell 4n+2 Möbius cycle has less π resonance energy than the equivalent (closed shell) untwisted Hückel cycle.
• The HMO solution has no geometric model: No Möbius surface assignable to eigenvectors.