Question

Which one of the following complexes is an outer orbital complex ?

• A. $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}$
• B. $\left[ Mn ( CN )_{6}\right]^{4+}$
• C. $\left[ Fe ( CN )_{6}\right]^{4-}$
• D. $\left[ Ni \left( NH _{3}\right)_{6}\right]^{2+}$

Answer 1

Answer: (D)

$\left[ Fe ( CN )_{6}\right]^{4-},\left[ Fe ( CN )_{6}\right]^{4-}$ and $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}$ involve $d^{2} sp ^{3}$ hybridization and are inner orbital complexes.
The compound $\left[ Ni \left( NH _{3}\right)_{6}\right]^{2+}$ involves $sp ^{3} d ^{2}$ hybridization and is outer orbital complex.