Assertion : Bond lengths of P-Cl bonds in gaseous PCl_5 and solid...

As in solid state, $\mathrm{PCl}_5$ exists as an ionic solid \left[\mathrm{PCl}_4\right]^{+}$\left[\mathrm{PCl}_6\right]^{-}$in which the cation, \left[\mathrm{PCl}_4\right]^{+} is tetrahedral and the anion, $\left[\mathrm{PCl}_6\right]^{-}$is octahedral. $\mathrm{PCl}_5$ in gaseous state has trigonal bipyramidal structure in which three equatorial bonds are equivalent, while the two axial bonds are longer than equatorial bonds due to more bond pair repulsion.