Due to the presence of six fluoride ligands and one lone pair of electrons in $\mathrm{X}\mathrm{e}{\mathrm{F}}_6$ , the structure lacks perfect octahedral symmetry and is disordered. In ${\left[\mathrm{X}\mathrm{e}{\mathrm{O}}_6\right]}^{4-}$ all the valence shell electrons of xenon are involved in the bonding with oxygen and hence, no lone pair of electrons is present. So, it has perfect octahedral geometry.