BCl_(3)is planar but anhydrous AlCl_(3)is tetrahedral . Explain .

1.	BCl_(3)is planar but anhydrous AlCl_(3)is tetrahedral . Explain .
Answer» Solution :In `BCl_(3)`, B atom is `sp^(2)` HYBRIDIZED . The three half-filled HYBRID orbitals overlap with the half-filled orbitals of CL atoms giving a triangular planar structure . Anhydrous `AlCl_(3)`exists as DIMER with the formula `Al_(2) Cl_(6)`whose structure is shown below : Thus, each Al atom is surrounded by four BOND paris and hence it assumes tetrahedral structure .

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