Question

Which of the following statements is/are true for $\left[Cu\right(N{O}_2{)}_6{]}^{4-}$and $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$?

• A. Both are outer orbitals complexes
• B. Both are inner orbitals complexes with magnetic moment equal to 1.73 B.M.
• C. The former complex is paramagnetic with one unpaired electron while later one is paramagnetic with five unpaired electrons
• D. The former is outer orbital complex and later is inner orbital complexes respectively

Answer 1

Answer: (A), (C)

The correct options are
A Both are outer orbitals complexes
C The former complex is paramagnetic with one unpaired electron while later one is paramagnetic with five unpaired electrons


In case of $\left[Cu\right(N{O}_2{)}_6{]}^{4-}$ inner d-orbitals are not available for $d^{2}s{p}^3$ hybridisation.
In case of $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$ as water is a weak field ligand so it will not cause pairing and will lead to $s{p}^3{d}^2$ hybridisation.