The electrons in a sigma bond (usually C–H or C–C) with an adjacent
empty (or partially filled) non-bonding p-orbital, antibonding p orbital, or filled p orbital, to give an
extended molecular orbital
that increases the stability of the system  are in hyperconjugation.Only electrons in bonds that are ß to the positively charged carbon can stabilize
a carbocation by hyperconjugation.


Hyper conjugation is a special type of resonance in which
delocalization of electrons takes place through overlap between sigma bond
orbital and pi-bond orbital or p- orbitals. For example take propene molecule,where it arises due to partial overlap of sp3-s sigma bond
orbital and the empty p-orbital or pi-bond orbital of an adjacent carbon atom.
Here one of the carbon-hydrogen bonds of methyl group can lie in the plane of
pi-bond orbital, hence partial overlap with pi-bond orbital. This results the
delocalization of pi-electrons and increase the stability of molecule.

 Thanks & regards
 Aarti Gupta
                                                       askiitians Faculty 
 
 
 





 
 
  
  
  
  
  
  
  
  
  
  
  
  
 
 
 

 



						

							Movement of sigma electrons through an adjacent pi system or a carbocation is called hyperconjugation. It involves sigma electron delocalization.The electrons of the sigma bond between C and H are also involved in delocalization and there is a no bond between C and H due to migration of electrons of the sigma bond.Hence hyper conjugation is also called no bond resonance.


Thanks & Regards
Ruchi Shaw
askIITians faculty