JEE Main · 2022 · 26 Jul 2022 · Shift 1 · Chemical Bonding and Molecular Structure

Applying VSEPR to each species fixes its shape. In $\mathrm{Br}{\mathrm{F}}_5$ bromine has five bond pairs and one lone pair, an $A{X}_{5}E$ arrangement, which is square pyramidal. The ion $[\mathrm{Cr}{\mathrm{F}}_6{]}^{3-}$ is a six-coordinate chromium(III) centre and is octahedral. Ozone, ${\mathrm{O}}_3$, has a central oxygen with one lone pair and two bonding regions, so it is bent. In $\mathrm{PC}{\mathrm{l}}_5$ phosphorus has five bond pairs and no lone pair, an $A{X}_5$ arrangement, so it is trigonal bipyramidal. The species therefore pair with square pyramidal, octahedral, bent and trigonal bipyramidal in turn. Note that it is $\mathrm{Br}{\mathrm{F}}_5$, not the square-planar ion $[\mathrm{Br}{\mathrm{F}}_4{]}^{-}$, that is square pyramidal.