Final answer:
The sigma bond between Xe and F in XeF4 involves an sp3d2 hybrid orbital from Xe.
Step-by-step explanation:
The atomic or hybrid orbital on xenon (Xe) that participates in forming the sigma bond between Xe and fluorine (F) in xenon tetrafluoride (XeF4) is an sp3d2 hybrid orbital.
According to the VSEPR model, the electron-pair geometry for Xe in XeF4 must accommodate six regions of high electron density consisting of four bonds and two lone pairs. This leads to a square planar molecular structure with an octahedral electron-pair arrangement, suggesting sp3d2 hybridization. Each Xe-F sigma bond in XeF4 involves the overlap of one sp3d2 hybrid orbital from Xenon and one p-orbital from Fluorine.