Isomerism in Coordination Compounds: Stereo and Structural Isomerism

• Stereo Isomerism
• Structure Isomerism

The video below explains this:

Isomerism in Coordination Compounds Detailed Video Explanation:

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Stereo Isomerism

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Stereo Isomerism is caused by the phenomenon of different arrangements of atoms or groups. It can further be divided in the following:

• Geometrical Isomerism

• This type of isomerism is caused in heteroleptic complexes. It gets triggered by varied geometrical arrangements of ligands. The two ligands X may appear next to each other in a cis isomer or against each other in a trans isomer in the formula [MX₂L₂]
• Following is a graphical representation of the same : 

• In the same way, in ochtahedral complexes [MX₂L₄], the appearance of the two ligands may be cis or tans as illustrated below:

• Optical Isomerism

• The plane of polarized light can be made to rotate as the solutions of coordination compounds are kept in the former’s path. The angle of rotation may be left or right. This rotation of plane polarized light is known as its Optical Activity. 
• Non-super imposable mirror images cause the phenomenon of Optical Isomerism. The former is called “enantiomers”. The reaction of the enantiomers is varied owing to the plane polarized light.
• The enantiomers are known as “dextrorotatry” when the plane polarized light is rotated by them clockwise. “Levorotatory” are the enantiomers that move the light in the reverse direction. 
• Below is an image given for Optical Isomers : 

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Structural Isomerism

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This variant of Isomerism is caused by the difference in coordinate compound structure. There are four types of Structural Isomerism as given below:

• Ionisation Isomerism

• This variant of Isomerism is found in the isomers that possess the same molecular formula, however, they ions in solution given by them is different.
• An example of Ionisation isomerism is as follows : 

                          [Cr(NH₃)Br]SO₄ and [Cr(NH₃)(SO₄)]Br

• Given below is an illustration of Ionisation Isomerism:

• Linkage Isomerism

• This type of Isomerism occurs when the isomers possess the same molecular formula but they have got different linking atoms. This phenomenon is triggered by the Ambident ligands.
• Below given is an example of Linkage Isomerism : 

                      [CO(NH₃)₅(NO₂)]²⁺ and [CO(NH₃)₅ (ONO)]²⁺

• Following is an illustration corroborating Linkage Isomerism : 

• Coordination Isomerism

• This variant of Isomerism is triggered with the presence of complex cation and anion and thorough exchange of coordination sphere.
• Below is an example of Coordination Isomerism :

[Pt (NH₃)₄] [Ni (CN)₄] and [Ni (NH₃)₄] [Pt (CN)₄]

• Given below is an illustration of Coordination Isomerism:

• Hydration Isomerism or Solvate Isomerism

• Hydration isomers possess the similar molecular formula. However, they have varied hydration water molecules. Following is an example:

                    [Cr (H₂O)₅Cl]Cl₂.H₂O and [Cr(H₂O)₄Cl₂]Cl.₂H₂O 

• Below given is an illustration showing Hydration Isomerism :

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