Chemistry · Covalent Bonding: Concept of electronegativity, Fajan's rule, dipole moment, Valence Shell Electron Pair Repulsion (VSEPR) theory and shapes of simple molecules
Which of the following shapes of is more stable and why? (i)
Which of the following shapes of \( S F_{4} \) is more stable and why? (i)
- A. (i) Lone pair at axial position is stable
- B. (ii) Lone pair at equatorial position is stable
- C. Both are equally stable due to \( l p \) -bp repulsion
- D. Both are unstable since \( S F_{4} \) has tetrahedral shape
Step-by-step solution
In SF4, the central sulfur atom has a trigonal bipyramidal electron geometry with one lone pair. Lone pairs experience greater repulsion when in axial positions (since they are 90° to three equatorial bonds) compared to equatorial positions (where they are 90° to two axial bonds and 120° to two equatorial bonds). Placing the lone pair equatorial minimizes repulsion, making the see-saw shape more stable.