Hybridization and Structure of XeOF4:

Hybridization:
The central atom in XeOF4 is xenon (Xe), which belongs to the noble gas family. Xenon has the electron configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6, with eight valence electrons. In the excited state, one of the 5p electrons is promoted to the 5d orbital to achieve a total of five orbitals available for bonding. Therefore, the hybridization of xenon in XeOF4 is sp3d2.

Structure:
XeOF4 adopts a square pyramidal structure with the xenon atom at the center. The four oxygen atoms are bonded to the xenon atom in a planar arrangement, while the fluorine atom occupies the apical position, pointing away from the plane. The lone pair of electrons on the xenon atom occupies one of the equatorial positions, resulting in a distorted octahedral geometry.

Hybridization and Structure of [CrF6]^3-:

Hybridization:
The central atom in [CrF6]^3- is chromium (Cr), which belongs to the transition metal family. Chromium has the electron configuration [Ar] 3d5 4s1, with six valence electrons. In order to form six bonds, the chromium atom undergoes hybridization. The hybridization of chromium in [CrF6]^3- is sp3d2, similar to the hybridization of xenon in XeOF4.

Structure:
[CrF6]^3- adopts an octahedral structure with the chromium atom at the center. The six fluoride ions are bonded to the chromium atom, occupying the six coordination positions. The octahedral geometry is achieved due to the sp3d2 hybridization of the chromium atom, which allows for the formation of six sigma bonds.

Overall, both XeOF4 and [CrF6]^3- exhibit sp3d2 hybridization, resulting in square pyramidal and octahedral structures, respectively. These hybridization and structure arrangements are determined by the number of available orbitals for bonding and the repulsion between electron pairs, which strive to minimize energy and achieve maximum stability.