The electromeric effect is the movement of electrons from one atom to another as a reagent attacks a π bond. +E effect: In the positive electromeric effect the pi electrons of the multiple bond are transferred to that atom to which the attacking reagent is bonded. -E effect. This lesson will discuss inductive, mesomeric and electromeric effects with examples. We will also discuss some of the factors affecting electron.

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Retrieved from ” https: We have the best tutors in Finance electromerix the industry. Homolytic fission is usually indicated by a fish arrow which denotes a one electron displacement. Your email address will not be published. This effect is temporary and takes place only in the presence of a reagent.

As soon as the reagent is removed, the polarized molecule will come back to the original state.

Electromeric effect is of two types: Our tutors are highly qualified and hold advanced degrees. It is temporary in nature because the molecule acquires its original electronic condition upon removal of the attacking reagent. Thus, methyl with three hydrogen atoms shows a greater effect when compared to ethyl with only two such hydrogen atoms.

Fission of a covalent bond.

Electronic Displacement Effects – Electromeric Effect

There are two types of inductive effect: The neutral chemical species which contain an odd or unpaired electron and which are produced by homolytic fission of covalent bonds are called free radicals. This electroeric weakens steadily with increasing distance from the substituent and actually becomes negligible after 3 carbon atoms. These effects include the electromeric effect and the hyperconjugation. When the inductive effect and the electromeric effect operate in the same molecule, electromeric effect dominates the inductive effect.


Homolytic fission usually effetc in non-polar bonds and is favoured by high temperatureultraviolet radiations and by the presence of radical indicators such as peroxides. In the meanwhile oxygen takes complete control of the electron pair and becomes negatively charged.

Chemistry | Organic Chemistry | – what is electromeric eff-askIITians

Click for More Uploads. Leave a Reply Cancel reply Your email address will not be published. When a covalent bond joining two atoms A and B breaks in such a way that both the electrons of the covalent bond are taken away by one of the bonded atoms, the mode of bond cleavage is called heterolytic fission. If the electrons of the double bond are transferred to an atom of the double bonds other than the one to which the reagent gets finally attached the effect is called -E Effect.

Please explain +E and -E electromeric effects with examples.

Solved problems Methyl amine is considered stronger than ammonia. The effect disappears as the attacking agent is removed. Heterolytic fission results in the formation of charged species i.


The -I effect of some of the atoms and groups in the decreasing order w. Heterolytic fission is usually indicated by a curved arrow which denotes a two electron displacement.

The -E effect can be found in reactions such as addition of nucleophiles to carbonyl compounds. This effect can best be represented as follows. Views Read Edit View history.

As the electromeric effect is seen only in the presence of an attacking agent, this effect is said to promote the reactions rather than inhibiting them.

Bond Polarization – Eletromeric Effects

Please do send us the Inductive Effect of Hyperconjugation Bond Polarization problems on which you need Help and we will forward then to our tutors for review. Greater the number of hydrogen atoms attached to the carbon atom greater will be the electron release.

The most common attacking reagents that initiate the electromeric effect are the polar reagents. From Wikipedia, the free encyclopedia. As they occur only in the presence of a attacking agent and disappear as the attacking agent is removed They exist only for certain time period.

Electromerjc these reactions, the electron pair moves away from the attacking reagent.