Discuss the different types of isomerism exhibi... - SS3 Chemistry Inorganic Chemistry: d-Block Elements Question

Types of Isomerism in Coordination Compounds:

1.    Structural Isomerism:

a.    Ionisation Isomerism: In ionisation isomers, the counter ions and ligands exchange places. For example, [Co(NH3)5Cl]SO4 and [Co(NH3)5(SO4)]Cl are ionisation isomers.

b.    Coordination Isomerism: In coordination isomers, ligands exchange places between the central metal ions. For example, [Co(NH3)6][Cr(CN)6] and [Cr(NH3)6][Co(CN)6] are coordination isomers.

2. Stereoisomerism:

a.    Geometric (Cis-Trans) Isomerism: This type of isomerism arises when ligands are arranged differently around a coordination complex. Common in octahedral complexes with bidentate ligands, like [Pt(NH3)2Cl2], which can exist in cis and trans isomers.

b.    Optical (Enantiomerism) Isomerism: Optical isomers are non-superimposable mirror images of each other. They arise when a coordination complex lacks a plane of symmetry. For example, [Co(en)3]3+ exists as two enantiomers, which are mirror images of each other.

Significance of Isomerism:

Isomerism in coordination compounds is of great significance as it provides valuable insights into the structural diversity and properties of these complexes. Different isomers can have distinct colours, stabilities, and reactivities, leading to diverse applications in fields such as catalysis, medicine, and materials science.

Understanding isomerism is crucial for designing coordination compounds with specific desired properties and functionalities. It allows chemists to tailor complexes to suit particular applications by selecting appropriate ligands, metal centres, and coordination geometries. Moreover, isomerism enhances our understanding of the intricate nature of coordination chemistry and contributes to the development of novel and efficient catalysts and materials.