This In-Class Activity is meant to follow up discussions of ligand field theory toward the end of MO theory including the effects of sigma donors, pi donors, and pi acceptors, and how it relates to absorption spectra and observed color of some transition metal complexes. Students have learned crystal field theory and the effects of geometry/symmetry on ∆, then we extend to LFT and how the chemistries of different ligands affect ∆.

This LO uses borane and carborane clusters to practice assigning point groups and counting electrons. It also asks students to recall electronegativity trends to predict dipoles, and they can check their predictions against calculated Mulliken charges.