Question

Number of possible isomers for the complex $\left[Co\right(e{n}_2\left)C{l}_2\right]Cl$ will be (en: ethylenediamine) is :

• A. 4
• B. 1
• C. 3
• D. 2

Answer 1

The correct option is C 3

Number of possible geometrical isomers for the complex $\left[Co\right(en{)}_{2}C{l}_2]Cl$ is 2 and are cis and trans.

In $\text{trans}-\left[CoC{l}_2\right(en{)}_2{]}^{+}$ both the (en) are at opposite position and are at same plane. So there will be a plane of symmetry which result in optical inactivity.

In $cis-\left[CoC{l}_2\right(en{)}_2{]}^{+}$, both the (en) ligands are at adjacent position, thus, both at different plane and hence it is optically active and gives a respective non-superimposable mirrow image enantiomer.

Hence, there are totally 3 possible isomers for the given complex.