Isomerism

Isomers are chemical compounds which has the identical chemical formulas but different in the characteristics and atomic arrangement in the molecule, as a result, the substances that displays isomerism are known as isomers.

“Isomer” comes from the Greek words “isos” and “meros,” which both imply “equal pieces.” In the year 1830, the Swedish chemist Jacob Berzelius created the word. 

Types of Isomerism

There are two main forms of isomerism, each of which can be further divided into subgroups. Structural Isomerism and Stereoisomerism are the two main forms. 

Structure Isomerism 

The isomerism in which the functional groups and atoms in these isomers’ molecules are linked in various ways is known as structural isomerism. Because structural isomers may or may not include the same functional group, they are given different IUPAC designations.

Butane and isobutane (C4H10) is example of Structure Isomerism.

Chain Isomerism 

Skeletal isomerism is another name for it.

These isomers’ constituents have different branching architectures, and the branching of carbon in chain isomers differs in most cases.

The organic compound C5H12 is an example of chain isomerism.

Position Isomerism

Position isomers are the isomerism in which the compounds differ in the locations of functional groups or substituent atoms. The attachment of functional groups to distinct carbon atoms in the carbon chain is typical of this isomerism.

The compounds with the formula C3H7Cl are a good example of this type of isomerism.

Functional Isomerism

Functional group isomerism is another name for the functional isomerism. It refers to compounds that have the same chemical formula but distinct functional groups linked to them, as the name suggests. The chemical molecule C3H6O is an example of functional isomerism.

Metamerism

The existence of distinct alkyl chains on each side of the functional group causes his type of isomerism, which is known as metamerism. Metamerism is a rare kind of isomerism that only occurs only in the compounds with a divalent element (like sulphur or oxygen) surrounded by alkyl groups.

Ethoxyethane (C2H5OC2H5) and methoxy-propane (C4H10O) are the two examples of C4H10O. (CH3OC3H7), which shows metamerism.

Tautomerism

The isomer of a chemical that only differs in the location of protons and electrons is referred to as a tautomer and the isomerism is known as tautomerism. In most of the cases, a compound’s tautomers coexist in equilibrium and are easily interchangeable and it happens as a result of an intramolecular proton transfer.

Keto-enol tautomerism is a good example of this phenomena of tautomerism.

Ring-Chain Isomerism

One isomer has an open-chain structure, whereas the other has a ring structure in ring-chain isomerism.

They usually have a varied amount of pi bonds in them.

The isomerism in C3H6 is a superb example of this type of isomerism. Propene and cyclopropane are the isomers that result.

Stereoisomerism

This sort of isomerism occurs in compounds that have the same chemical formula but distinct three-dimensional orientations of the molecule’s atoms. Stereoisomers refer to chemicals that exhibit stereoisomerism. This phenomenon can be further divided into two categories. This subsection briefly describes both of these categories:

Geometry Isomerism

It’s referred to as cis-trans isomerism.

In three-dimensional space, these isomers have various spatial configurations of atoms.

The geometric isomerism seen in the acyclic But-2-ene molecule.

Optical Isomerism

Optical isomerism occurs when a compound has comparable bonds but differing spatial arrangements of atoms, resulting in non-superimposable mirror images.

Enantiomers are another name for optical isomers.

The optical activity of enantiomers differ from one another. Dextro enantiomers rotate the plane of polarised light to the right, while laevo enantiomers rotate it to the left.

butan-2-ol is one example of Optical Isomerism.

Ionization Isomerism

Ionization isomers are compounds that produce distinct ions in solution despite having the same composition, and this trait is known as ionisation isomerism. Ionization isomerism refers to compounds that produce distinct ions in solution despite having the same chemical composition. When the counter ion in a complex salt is also a potential ligand, it can displace a ligand, which can then become the counter ion, resulting in isomerism.

[Co(NH3)5SO4]Br and [Co(NH3)5Br]SO4 are two examples of ionisation isomerism.

Conclusion

Therefore, Isomers are chemical compounds which has the identical chemical formulas but different in the characteristics and atomic arrangement in the molecule, as a result, the substances that displays isomerism are known as isomers. There are two main forms of isomerism, each of which can be further divided into subgroups. Structural Isomerism and Stereoisomerism are the two main forms.