Isomerism in coordination compounds refers to the existence of two or more different compounds with the same chemical formula but different arrangements of atoms or groups. There are two main types of isomerism observed in coordination compounds: structural isomerism and stereoisomerism.1. Structural Isomerism: This type of isomerism arises due to the differences in the arrangement of ligands around the central metal ion. There are three sub-types of structural isomerism:a Coordination Isomerism: This occurs in mixed-ligand complexes where the ligands can exchange positions between the coordination spheres of two different metal ions. To distinguish between them experimentally, one can perform a chemical analysis to identify the ligands in the coordination sphere of each metal ion.b Linkage Isomerism: This occurs when a ligand can coordinate to the central metal ion through different donor atoms. For example, the nitrite ion NO2- can bind through either the nitrogen or oxygen atom. To distinguish between them experimentally, one can use spectroscopic techniques like infrared IR spectroscopy or X-ray crystallography to determine the bonding site of the ligand.c Ionization Isomerism: This occurs when a counter-ion in the compound can be replaced by a ligand, resulting in different anions or cations. To distinguish between them experimentally, one can perform a chemical analysis to identify the anions or cations present in the compound.2. Stereoisomerism: This type of isomerism arises due to the different spatial arrangements of ligands around the central metal ion. There are two sub-types of stereoisomerism:a Geometrical Isomerism: This occurs in complexes with square planar or octahedral geometries, where the ligands can occupy different positions relative to each other. For example, cis and trans isomers in square planar complexes. To distinguish between them experimentally, one can use spectroscopic techniques like UV-Visible spectroscopy or X-ray crystallography to determine the spatial arrangement of the ligands.b Optical Isomerism: This occurs when a coordination compound is non-superimposable on its mirror image, resulting in a pair of enantiomers. These compounds are optically active and can rotate plane-polarized light. To distinguish between them experimentally, one can use polarimetry to measure the optical rotation or use chiral chromatography to separate the enantiomers.In summary, the different types of isomerism observed in coordination compounds are structural isomerism coordination, linkage, and ionization isomerism and stereoisomerism geometrical and optical isomerism . Various experimental techniques like chemical analysis, spectroscopy, X-ray crystallography, polarimetry, and chiral chromatography can be used to distinguish between these isomers.