I think my favorite would be the one in which they (as a class) construct their own MO diagram of a transition metal complex. The first time it "clicks" and they are able to do it as a class varies from year to year, but the day that it does is the high point of the course.

I have 2 favorite lectures, well, 3.  Werner, nitrogenase, and my "Nobel prizes in electron transfer through the ages." where I summarize Arrhenius, Werner, Marcus and Taube in one lecture.  whew, that one is fun. 

But, my Werner lecture is my favorite.  I go through a historical perspective, with Werner and Jørgensen battling it out over chain theory vs. what would eventually be called Werner theory.  Isomer counting, synthetic methods, chirality, all that great stuff.  I present data and students rule out what can't be true, and at the end, hey, they must be octahedral!  At the end, I say, he was skilled, but lucky.  Try this with Cr(II) or Co(II).

 I also do a historical perspective when I discuss Haber and ammonia, with the added fun of discussing bat guano in lecture.  I usually try to discuss the implications of NH3 on the length of WWI, and I end this depressing tale with the suicide of his first wife in opposition of his work with chemical weapons.  I don't try to get preachy here, just illustrate the science and society are not separate things.

My ET tour-de-force discusses the following chemical reaction through the ages:

Cr(III) + Co(II) --> Cr(II) + Co(III)

and we include inner/outer sphere ET, Werners description of the complexes (Cr(III) contains a chloride that bridges and Co(III) has the Cl at the end), Marcus theory of ET rates, and the Creutz-Taube ion.

These 3 lectures are really more about me having fun and showing historical perspectives rather than expecting them to know it all.  They serve as introductory lectures for the rest of the unit that I can then refer back to from time to time.

Adam

In my intro class at the end of the semester we are talking about metals and ligands and crystal field splitting and since I have so many biology and biochemistry students in the class, I like to point out that colors of venous and arterial blood and even the cooperativity of the subunits in hemoglobin can be related to what is going on in the coordination sphere of the metal. Some of the students have already seen the biochemists' version of how this works in biochem (our curriculum is very non-linear), and I like to say--this is why inorganic chemistry is so important for all of you to know! heppley@depauw.edu