This Lewis structure and VSEPR problem is based on a paper from Inorganic Chemistry in 2010 reporting the crystal structures of a series of salts of the [XeF]⁺ cation.  The [MF₆]^– and [M₂F₁₁]^– anions (M = As, Sb, Bi) were used as counterions, and in all cases, the [XeF]⁺ cation interacts with the anion via a weak bond between the Xe and a fluoride of the anion to form an ion-pair in the crystalline solid.  These somewhat unusual ions provide an interesting application of the predictive powers of Lewis stru

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

This activity makes use of Jmol animations created by Prof. Marion Cass at Carleton College to illustrate the Berry Pseudorotation in trigonal bipyramidal molecules such as PF₅.  Students explore the animations and answer a series of questions that lead to a description of this intramolecular motion that exchanges equatorial and axial atoms in trigonal bipyramidal molecules.  

Link to Jmol animations of Berry Pseudorotation