Xenon atom in XeO4 undergo sp3 hybridization.
In the fourth excited state, xenon atom has 8 unpaired electrons
One s and three p orbitals undergo sp3 hybridization. Four sp3 hybrid orbitals form four σ bonds with oxygen atoms. They are σsp3−p bonds. Four pπ−dπ bonds are also formed with oxygen atoms by the unpaired electrons in the d orbitals of xenon.