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Question
The CFSE for octahedral \[\ce{[CoCl6]^{4-}}\] is 18,000 cm–1. The CFSE for tetrahedral \[\ce{[CoCl4]^{2-}}\] will be ______.
Options
18,000 cm–1
16,000 cm–1
8,000 cm–1
20,000 cm–1
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Solution
The CFSE for octahedral \[\ce{[CoCl6]^{4-}}\] is 18,000 cm–1. The CFSE for tetrahedral \[\ce{[CoCl4]^{2-}}\] will be 8,000 cm–1.
Explanation:
CFSE for octahedral and tetrahedral complex is related as
`Δ^t = 4/9 Δ_o`
Where `Δ_o` = CFSE for octahedral complex
`Δ_o` = CFSE for tetrahedral complex
`Δ_o` = 18000 cm–1
`Δ_t = 4/9 xx 18000` = 8000 cm–1
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