Breaking down the physics-chemistry divide

Chemists and physicists tend to talk different languages, including when discussing the same thing. One important parallel is the common concept of the molecular orbitals in a molecule and the energy bands in a crystal. Specifically, the Huckel method to describe electronic properties of conjugated organic molecules is identical to the tight-binding method in solid state physics.

Yet these important parallels seem to rarely be pointed out in textbooks. [One exception is a brief mention in Walter Harrison's Electronic Structure and the Properties of Solids].
Recently when I have taught solid state I have pointed out the connection and sometimes worked through the nice treatment of Huckel theory in chapter 8 of the classic book Coulson's Valence by Roy McWeeny.

Besides showing the molecule-solid connection this can illustrate a few useful things including:

• How Bloch's theorem works in a finite system.
• How energy bands emerge in the thermodynamic limit (see above).
• The correspondence between bonding (anti-bonding) orbitals in a molecule and valence (conduction) bands in a crystal.
• The potential importance of electron-electron interactions, which are completely neglected in both Huckel and tight-binding approximations. Valence bond theory takes these interactions into account.

Any other ideas?

Some of the above parallels are explored in more detail in a beautiful article How Chemistry and Physics meet in the Solid State by Roald Hoffmann, and in a forthcoming book chapter by Ben Powell.