JEE Main · 2021 · 17 Mar 2021 · Shift 1 · Chemical Bonding and Molecular Structure

Two lone pairs and three bond pairs make five electron domains round the central atom, so the electron-pair geometry is trigonal bipyramidal and the hybridisation is $s{p}^{3}d$. A lone pair needs more room than a bond pair, and an equatorial site has only two neighbours at $90^{\circ }$ against three for an axial site, so both lone pairs take equatorial positions. The three bond pairs then occupy the two axial sites and the one remaining equatorial site, and three bonds placed this way give a T-shaped molecule, as in $\mathrm{Cl}{\mathrm{F}}_3$.