This Lewis structure and VSEPR problem is based on a paper from Inorganic Chemistry in 2010 reporting the crystal structure of the carbonyl diazide molecule. This relatively simple molecule provides an interesting application of the predictive powers of Lewis structures and VSEPR theory to molecular structure, backed up by experimental data on bond distances and bond angles. Before tackling carbonyl diazide, the students warm up by considering the structures of hydrogen azide and the isolated azide ion. The reference to the original paper is Inorg. Chem. 2010, 49, 9694-9699.
In answering these questions, a student will:
- Practice drawing multiple resonance structures for a molecule, assigning formal charge, and identifying major vs. minor resonance contributors based on considerations of formal charge distribution
- Gain experience applying VSEPR to predict the molecular structure and approximate bond angles in different molecules
- Relate the predictions of relatively simple theories to actual experimental results obtained from X-ray crystallography
This was assigned as a problem to be worked at the board by small groups during a conference session for a second-year inorganic chemistry course. I have also used it in a conference for general chemistry students.