JEE Main · 2004 · 24 Apr 2004 · Offline · Chemical Bonding and Molecular Structure

Count the $90^{\circ }$ angles between bond pairs that each geometry forces. An octahedron, produced by $s{p}^3{d}^2$ hybridisation, sets its six bonds along three mutually perpendicular axes and so carries the greatest number of $90^{\circ }$ angles. The trigonal bipyramidal $s{p}^{3}d$ and $ds{p}^3$ shapes and the square planar $ds{p}^2$ shape all offer fewer, so $s{p}^3{d}^2$ gives the maximum number of such right angles.