Which of the following ion pairs are incorrect for the given substance?

Trigonal bipyramidal shape is shared by ${\mathrm{PCl}}_5$ and $PB{r}_5$. This construction lacks regularity and stability. In order to form more sturdy octahedral and tetrahedral structures, ${\mathrm{PCl}}_5$ fragments. which have more stability than trigonal bipyramidal.

${\mathrm{PCl}}_5\rightleftharpoons {\left[{\mathrm{PCl}}_6\right]}^{-}{\left[{\mathrm{PCl}}_4\right]}^{+}$

In contrast, as $PB{r}_5$ fragments, a stable tetrahedral structure

$\begin{array}{l}{\left[{\mathrm{PBr}}_4\right]}^{+}[\mathrm{Br}{]}^{-}\\ {\mathrm{PCl}}_5\rightleftharpoons {\left[{\mathrm{PBr}}_4\right]}^{+}[\mathrm{Br}{]}^{-}\end{array}$

Due to the size of Br atoms and the difficulty of fitting six Br atoms around a smaller Br atom, this splitting differs from${\mathrm{PCl}}_5$ splitting.