Question

For the complex ion $\left[Fe\right(CN{)}_6{]}^{3-}$, state:
(i) the type of hybridisation.
(ii) the magnetic behaviour.
(iii) the oxidation number of the central metal atom.

Answer 1

In $\left[Fe\right(CN{)}_6{]}^{-3}$ complex $CN$ is a strong field ligand therefore will form low spin complex by using inner 3d-orbitals. Since it has octahedral geometry as there are 6 ligands, so its hybridization will be $d^{2}s{p}^3$.

The central metal has oxidation number $+3$ calculated as:

$x+6\times (-1)=-3$

Fe has $4s^{2}3d^6$ configuration and therefore $F{e}^{3+}$ will be $3d^5$. Upon pairing it has one unpaired electron that makes it paramagnetic complex.