This short communication in 2001 established the structure of a dinuclear cobalt complex based on a single crystal X-ray diffraction study of crystals taken from the Werner collection. The X-ray structure clarified the nature of the bridging ligands including a bridging superoxo group. As such, it offers a nice entry point into the nomenclature of bridging ligands, a discussion of O2 related ligands such as peroxide and superoxide, and the evolution of characterization techniques from Werner's time to the present.
I first used this as a problem set question rather than an in-class activity. I spent so much time talking to groups of students during office hours to clarify the concepts that I think it would have worked much better as an in-class discussion. If you have VIPEr Faculty Status, you will find solutions to these questions under the Problem Set activites (follow the link to related activities above).