2. DEFINITION
• The Electromeric effect (E Effect) refers to the polarity produced in a multiple bonded
compound as it is approached by a reagent.
• Temporary effect.
• Takes place only in the presence of a reagent.
3. • The electromeric effect is represented as:
• When a double or triple bond is exposed to an electrophile (a reagent). The two π
electrons which form the π bond are completely transferred to one atom or the other.
4. • Take an example of ethylene, when an electrophile attacks a carbon-carbon double bond
in the ethylene molecule. We know that the double bond is made up of one sigma bond
and one π bond. The electrons in the π bond are quite exposed. Under the influence of
the electric field of the positively charged electrophile, the symmetry of the molecular
orbital is disturbed entirely in favor of one carbon atom.
5.
6. Addition takes place according to Markownikoff's rule which states that the
negative portion of attacking reagent goes to carbon atom containing lesser number
of hydrogen atoms.
