Question -
Answer -
The ground state andexcited state outer electronic configurations of phosphorus (Z = 15) are:
Phosphorus atom is sp3d hybridized in theexcited state. These orbitals are filled by the electron pairs donated by fiveCl atoms as:
PCl5
The five sp3d hybrid orbitals aredirected towards the five corners of the trigonal bipyramidals. Hence, thegeometry of PCl5 can be represented as:
There are five P–Cl sigma bonds in PCl5. Three P–Cl bonds lie inone plane and make an angle of 120° with each other. These bonds are calledequatorial bonds.
The remaining two P–Clbonds lie above and below the equatorial plane and make an angle of 90° withthe plane. These bonds are called axial bonds.
Asthe axial bond pairs suffer more repulsion from the equatorial bond pairs,axial bonds are slightly longer than equatorial bonds.