Question

The possible number of optical isomers in [Co(en)2Cl2]+ are
A . 2
B . 3
C . 4
D . 6

Answer 1

Hint: In this question we have to use the concept of optical isomers of a coordination compound and find out the number of optical isomers in [Co(en)2Cl2]+.
Optical isomerism is a form of stereoisomerism. The mirror images of substances that cannot be overlaid on one another are known as optical isomers. As a result, the cis isomer can create two enantiomers that include itself. Depending on their ability to spin plane polarised light, optical isomers have names like dextro and laevo.

When it comes to molecular weight, as well as chemical and physical attributes, optical isomers are identical.

Complete answer:Isomers are species with the same molecular structure but distinct characteristics. Stereoisomers and structural isomers are the two primary groups of isomers. Linkage isomerism, coordination isomerism, ionisation isomerism, and solvate isomerism are some more subcategories of structural isomerism.

The given complex has stereoisomers and it does not have structural isomers. The polarized light's plane can be rotated by one of this complex's isomers. Additionally, it has geometric isomers. The two geometric isomers of the given molecule are cis and trans.


A plane of symmetry is present in the trans form, making it optically inactive. d and l optical isomers of cis are possible. It exhibits optical isomerism and is a complex of type [M(AA)2B2]. Since it lacks a plane of symmetry, its cis form can be divided into two optically active isomers. Because of its plane of symmetry, the trans isomer lacks an optical active form.

Here, one isomer is laevorotatory and one is dextrorotatory. As a result, we learned that the provided molecule had a total of 3 isomers.

The correct answer is B.

Note: The majority of didentate ligand-based octahedral complexes can exhibit optical isomers. It is impossible to foresee which isomer will be laevorotatory and which will be dextrorotatory. It must be discovered experimentally.
In the cis form of [Co(en)2Cl2]+, there are two Cl ligands and two en ligands right next to one another. Two Cl ligands and two en ligands are in direct opposition to one another in the trans form.