Name: Nomenclature of Coordination Compounds - I
Uploaded: 2019-07-19
Duration: 7 min 4 s
Description: All the chemical compounds are assigned a name, which is done according to a specific rule. How are coordination compounds named? Let’s watch the video to fi...

Question

Draw qualitatively energy level diagram showing

d

-orbital splitting in the octahedral environment. Predict the number of unpaired electrons in the complex

{[Fe {(CN)}_{6}]}^{4 -}

. Is the complex diamagnetic or paramagnetic? Is it coloured? Explain.

Accepted Answer

The complex ion ${[Fe {(CN)}_{6}]}^{4 -}$ has iron $(II)$ as a central metal ion and six cyano ( ${CN}^{-}$ ) ligands, and this complex ion is octahedral.

The configuration of ${Fe}^{2 +}$ is $3 d^{6} 4 s^{0}$

$\underset{3 d}{[⇅] [↑] [↑] [↑] [↑]} \underset{4 s}{[]}$

During the formation of this complex ion, the degeneracy of the $d$ -orbitals are lifted, and these are split into a set of two higher energy $d$ -orbitals namely $e_{g}$ ( $d_{x^{2} - y^{2}}$ and $d_{z^{2}}$ ) and another set of three lower energy orbitals called $t_{2 g}$ ( $d_{xy}, d_{yz}, d_{zx}$ ). The octahedral crystal field energy level diagram is as shown below:

The electronic configuration of ${Fe}^{2 +} : {d_{xy}}^{2} {d_{yz}}^{2} {d_{zx}}^{2} {d_{x^{2} - y^{2}}}^{0} {d_{z^{2}}}^{0}$ ( ${t_{2 g}}^{6} {e_{g}}^{0}$ ). Since ${CN}^{-}$ is a strong field ligand, it causes the pairing of electrons in $t_{2 g}$ -orbital. This complex ion is diamagnetic as there are no unpaired electrons in the molecule.

Since, all the $d$ -electrons are paired up, there is no $d - d$ transition, hence the complex is colourless.

Draw qualitatively energy level diagram showing $d$ -orbital splitting in the octahedral environment. Predict the number of unpaired electrons in the complex ${[Fe {(CN)}_{6}]}^{4 -}$ . Is the complex diamagnetic or paramagnetic? Is it coloured? Explain.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Draw qualitatively energy level diagram showing d-orbital splitting in the octahedral environment. Predict the number of unpaired electrons in the complex FeCN64-. Is the complex diamagnetic or paramagnetic? Is it coloured? Explain.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Draw qualitatively energy level diagram showing $d$ -orbital splitting in the octahedral environment. Predict the number of unpaired electrons in the complex ${[Fe {(CN)}_{6}]}^{4 -}$ . Is the complex diamagnetic or paramagnetic? Is it coloured? Explain.