Final answer:
The hybridization of Al in AlF3 typically involves the mixing of the aluminum atom's 3s and 3p orbitals to form sp2 hybrid orbitals, but the compound's covalent character makes the hybridization a more complex topic involving possibly a higher state such as the use of d orbitals.
Step-by-step explanation:
The hybridization of aluminum (Al) in aluminum trifluoride (AlF3) involves the reorganization of the 3s, the three 3p, and two of the 3d orbitals after the aluminum has formed an Al3+ ion. This ion formation occurs as aluminum loses its 3-level electrons. In the case of AlF3, this process results in hybrid orbitals capable of forming bonds with the fluoride ions.
Given that Al in AlF3 is surrounded by three fluoride ions, we might expect the aluminum ion to use three hybrid orbitals to accept lone pairs from the fluoride ions. However, when considering the actual structure and properties of AlF3, the picture suggests a significant degree of covalent bonding, which still involves hybridization of atomic orbitals.
In summary, while the precise hybridization state of Al in AlF3 can be a complex topic due to its covalent character, we take into consideration the coordination number and the electron geometry, suggesting a possible sp2 or a higher hybridization state involving d orbitals, though the latter is less common in the main group elements.