JEE Main · 2023 · 06 Apr 2023 · Shift 1 · Chemical Bonding and Molecular Structure

A square pyramidal shape arises from an $s{p}^3{d}^2$ (octahedral) electron geometry carrying exactly one lone pair on the central atom. Testing each species: ${\mathrm{PF}}_5$ is $s{p}^{3}d$ with no lone pair and is trigonal bipyramidal; ${\mathrm{BrF}}_4^{-}$ is $s{p}^3{d}^2$ with two lone pairs and is square planar; ${\mathrm{IF}}_5$ is $s{p}^3{d}^2$ with one lone pair and is square pyramidal; ${\mathrm{BrF}}_5$ is $s{p}^3{d}^2$ with one lone pair and is square pyramidal; ${\mathrm{XeOF}}_4$ is $s{p}^3{d}^2$ with one lone pair and is square pyramidal; ${\mathrm{ICl}}_4^{-}$ is $s{p}^3{d}^2$ with two lone pairs and is square planar. The number of square pyramidal species is 3.