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 exercise was developed to help students predict bonding between s,p and d atomic orbitals.

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.

Students work individually, then compete in teams, to identify symmetry elements and operations present in a high-symmetry structure, such as an octahedron or tetrahedron (without showing the character table until the end of the activity).  Students often  visualize symmetry elements differently from one another.  Creating teams, allows them to work collaboratively, and the competition adds an incentive for finding the most elements.  Since some students are better at seeing some symmetry elements (and operations) than others, it allows for them to work in small groups to both teach and lea