How do you explain hybridisation of i3-?

The hybridization of the triiodide ion (I₃⁻) involves the central iodine atom, which is surrounded by two iodine atoms and one extra electron due to the negative charge. The central iodine undergoes sp³ hybridization to form three equivalent hybrid orbitals, which accommodate the bonding with the two peripheral iodine atoms and the lone pair of electrons. The resulting molecular geometry is linear, with the two iodine atoms positioned 180 degrees apart, while the lone pair is in the equatorial position. This arrangement minimizes electron pair repulsion according to VSEPR theory.