Which of the following species exhibits a perfectly linear molecular geometry despite possessing mul — Chemical Bonding Chemistry Question

💡 Solution & Explanation

In the triiodide ion ($I_3^-$), the central iodine ($sp^3d$) has 2 bond pairs and 3 lone pairs. The 3 lone pairs symmetrically occupy the equatorial plane ($120^\circ$ apart) to cancel repulsions, forcing the 2 iodine atoms into the axial positions ($180^\circ$), resulting in a linear shape.