Why are the P-Cl bonds in `PC l_(5)` not of same length?

Explanation

In `PCl_(5)`, two axial P-Cl bonds and three equatorial P-Cl bonds are present. An axial bond pair is repelled by three equatorial bond pairs at `90^(@)` and one axial bond pair at `180^(@)`. Similarly, an equatorial bond pair is repelled by two axial bond pairs at `90^@` and two equatorail bond pairs at `120^(@)`. thus, an axial bond pair is repelled by three electron pairs while an equatorial bond pair is repelled by two electron pairs. thus, axial bond pair is repelled by two electron pairs. thus, axial bond pair suffers greater repulsion & hence slightly longer than equatorial bonds.