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प्रश्न
BCl3 exists as monomer whereas AlCl3 is dimerised through halogen bridging. Give reason. Explain the structure of the dimer of AlCl3 also.
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उत्तर
Both the compounds, BCl3 and AlCl3 are electron-deficient compounds. In BCl3, boron is smaller in size and cannot assemble four big chlorine atoms near it causing steric hindrance and making it unstable.
Hence, BCl3 exists as a monomer only.
In AlCl3, aluminum has 3p-orbitals through which chlorine atoms can be accommodated easily to complete its octet and dimer is formed.
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