A guided inquiry activity where students use group theory and character tables to practice determining reducible representations for all atoms and the individual bonds (like CO stretches).  The students then reduce the representation, determine which are vibrational modes, and then determine which are IR active using the character table.  For the second portion, they practice using this approach to differentiate between two metal isomers.

The following is a simple in-class “demonstration” that I use to segue between d to d and charge transfer transitions.  After teaching about d to d transitions and Tanabe-Sugano Diagrams, I show my students three solutions that I have put in large test tubes before class. The three solutions I place in the test tubes are:

a.  10 ml of 0.1M Co(H₂O)₆²⁺

b.  10 ml of 0.1M Cu(H₂O)₆²⁺

c.  10 ml of a freshly prepared 0.1 M KMnO₄ solution

This in-class activity walks students through the preparation of a molecular-orbital diagram for methane in a square-planar environment.  The students generate ligand-group orbitals (LGOs) for the set of 4 H(1s) orbitals and then interact these with carbon, ultimately finding that such a geometry is strongly disfavored because it does not maximize H/C bonding and leaves a lone pair on C.

This activity is meant to teach students an MO theory interpretation of hypervalency that goes beyond the simple (and somewhat unsatisfying) explanation that atoms that are in the third row and below use d-orbitals for bonding in addition to s- and p-orbitals. Specifically, students will be learning how to construct MO diagrams for multicenter bonding schemes (i.e., 3c4e).  

This in-class activity traces the many contributions leading to the correct assignment for the solid-state structure of triiron dodecacarbonyl, [Fe₃(CO)₁₂],  with the aim of reinforcing ideas about IR spectroscopy and group theory. I give this activity to my advanced inorganic chemistry class (graduate students and senior undergrads). The activity is loosely based on the paper: Desiderato, R., Jr.; Dobson, G. R. J. Chem. Educ. 1982, 59, 752-756 and incorporates questions about symmetry and group theory for metal carbonyls.