Question

Explain the geometrical and optical isomerism of coordination compounds with coordination number 4, giving a suitable example (Minimum 4 examples).

Answer 1

In compounds with CN 4 & 6, geometrical isomers would be simply cis and trans type irrespective of the type of ligand, monodentate or bidentate. As regards optical isomers, it is a bit complicated situation.

If a molecule is asymmetric, it cannot be superimposed on its mirror image. The two forms are called enantiomorphic pair and are optical isomers. These are called dextro and laevo or d and l forms. In case of bidentate ligand in octahedral complexes, it is very common. For example in [Co(en)2Cl2]+, it shows cis and trans forms as geomtrical isomers. In addition, cis form is optically active and exists as d and l forms. . T