Question

The total number of unpaired electrons present in the complex ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$ is

Answer 1

Potassium trioxalato chromate $\left(\mathrm{III}\right)$ ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$ :

• The IUPAC name of ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$ is potassium trioxalato chromate $\left(\mathrm{III}\right)$.
• The coordination number will be 6 as it is bonded to three bi-dentate ligands.
• The coordination number of the compound is the number of ligands attached to the central metal ion denticity of its ligand.

Unpaired electron ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$:

• Chromium is in $+3$ oxidation state
• $\mathrm{Cr}\to 3{\mathrm{d}}^{5}4{\mathrm{s}}^1$.
• $\mathrm{Cr}\to 3{\mathrm{d}}^{5}4{\mathrm{s}}^1$ have $3$ unpaired electron the hybridization of chromium in the complex is ${\mathrm{d}}^2{\mathrm{sp}}^3$.

Therefore, the total number of unpaired electrons present in the complex ${\mathrm{K}}_3\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$ are 3.