Question

What is the hybridisation of the metal in the following complex?

$\left[Fe\right(H_{2}O{)}_6{]}^{3+}$

• A. $s{p}^{3}d$
• B. $s{p}^3{d}^2$
• C. $sp{d}^3$
• D. None of these

Answer 1

Answer: (B)

$s{p}^3{d}^2$

Option (B) is correct.

The iron atom in the complex $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$ shows $s{p}^3{d}^2$ hybridisation and has octahedral geometry.

The $Fe$ atom in $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$ has +3 oxidation state as the water ligands are neutral. The electronic configuration of $Fe\left(0\right)$ in the gas phase is $\left[Ar\right]3d^{6}4s^2$ and in the complex $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$ is $\left[Ar\right]3d^5$. The $3d$ shell is half filled and electron do not pair up as $H_{2}O$ is weak ligand. $4s$,three $4p$ and two $4d$ orbitals hybridized to form six $s{p}^3{d}^2$ hybrid orbitals.
Each $H_{2}O$ donates 6 electrons to the hybrid orbitals.