Find the number of species where $d_{x^2-y^2}$ orbital participates in hybridisation.

$\begin{array}{l}{\mathrm{XeF}}_6\hspace{0.25em} \hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{\mathrm{SF}}_6\hspace{0.25em} \hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{\mathrm{IF}}_7\\ {\mathrm{XeO}}_3 \hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{\mathrm{PCl}}_5\hspace{0.25em} \hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{\mathrm{PF}}_5\end{array}$

The number of species where $d_{x^2-y^2}$ orbital participates in hybridisation is 3.The species are ${\mathrm{XeF}}_6,{ \mathrm{SF}}_6,{ \mathrm{IF}}_7$.

${\mathrm{XeF}}_6$ has $d_{x^2-y^2}$ orbital participates in hybridisation. Because there are three 3p orbitals, two 3d orbitals, and one 3s orbital participate in hybridization. The six ${\mathrm{sp}}^3{\mathrm{d}}^2$ hybrid orbitals are aimed in the direction of the six regular corners of an octahedron.