Why the ion ICL4- is square planer?

The ion ICl₄⁻ has a square planar geometry due to its molecular shape resulting from the arrangement of electron pairs around the iodine atom. Iodine has four bonding pairs of electrons from the four chlorine atoms and two lone pairs. According to VSEPR theory, the repulsion between the lone pairs and bonding pairs leads to a configuration that minimizes steric hindrance, resulting in the square planar shape. The lone pairs occupy positions above and below the square plane formed by the chlorine atoms.