Describe the change in hybridisation (if any) of the Al atom in the following reaction.
The valence orbital picture of aluminum in the ground state can be shown as:
The orbital picture of aluminum in the excited state can be shown as:
Hence, it undergoes sp2 hybridization to give a trigonal planar arrangement (in AlCl3). To form AlCl4–, the empty 3pz orbital also gets involved and the hybridization changes from sp2 to sp3. As a result, the shape becomes tetrahedral.
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