Question

In which of the following complex ion, the central matal ion is in a state of $s p^{3} d^{2}$ hvbridisation?

• A. $\left[ COF _{6}\right]^{3-}$
• B. $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}$
• C. $\left[ Fe ( CN )_{6}\right]^{3-}$
• D. $\left[ Cr \left( NH _{3}\right)_{6}\right]^{3+}$

Answer 1

Answer: (A)

$F ^{-}$is a weak ligand. It cannot pair up $d$-electrons and forms outer orbital octahedral complex.
$NH _{3}$ and $CN ^{-}$are strong ligands. So, they pair up $d$-electrons and form their inner orbital complex.