Question

When observing/measuring the structures (abxey) in part b of the procedure, were you able to confirm that lone pair orbitals require more space than bonding pair orbitals? In the structures with five domains, which position did the bigger balloons (lone pairs) prefer, axial or equatorial? Describe your results in 2-3 sentences.

Answer 1

Lone pair orbitals indeed require more space than bonding pair orbitals, and in structures with five domains such as SF₄ (AX₄E), the lone pair prefers the equatorial position to minimize repulsions, resulting in a more stable structure.

Step-by-step explanation:

When observing the structures with five electron domains, it was confirmed that lone pair orbitals require more space than bonding pair orbitals. For molecules like SF₄, which have an AX₄E structure (four bonding pairs and one lone pair), the lone pair prefers the equatorial position over the axial one because this minimizes repulsion. In structures with lone pairs in the equatorial position, there are fewer 90° LP-BP repulsions, making them more stable than if the lone pair was placed in the axial position.

Similarly, in a molecule like AX₃E₂, which possesses three bonding pairs and two lone pairs, placing the lone pairs in the equatorial positions minimizes the number of 90° LP-BP repulsions compared to placing them in the axial positions. Therefore, in structures that are trigonal bipyramidal, lone pairs are expected to occupy equatorial positions to reduce repulsion and provide a more stable configuration.