Question

Which of the following is ore stable and why? ${\left[Co{\left({NH}_3\right)}_3\right]}^{3+}$ and ${\left[Co{\left(en\right)}_3\right]}^{3+}$. Name the following coordination compound and draw its possible structures $\left[CoC{l}_2{\left(en\right)}_2\right]Cl$

Answer 1

${\left[Co{\left(en\right)}_3\right]}^{3+}$ is more stable than ${\left[{Co\left({NH}_3\right)}_6\right]}^{3+}$

Because in complex compounds, the complex compound which has more chelation is stable than a compound which has chelation. Polydentate ligands and bidentate ligands have more chelation than monodentate ligand. Hence, ${\left[{Co\left(en\right)}_3\right]}^{3+}$ which has a bidentate ligand is more stable than ${\left[Co{\left({NH}_3\right)}_6\right]}^{3+}$ which has a monodentate ligand.

Chelation :- It is a type of bond in complex compounds where there is a formation of two or more separate co-ordinate bonds between a polydentate ligand and metal atom.

$\left[{CoCl}_2{\left(en\right)}_2\right]Cl$ is known as Dichloro bis(ethylenediamine) cobalt (III) chloride structure of $\left[{CoCl}_2{\left(en\right)}_2\right]Cl$.