The document discusses various reaction intermediates such as carbocations, carbanions, free radicals, carbenes, and benzyne. It highlights the characteristics, structures, and stability factors of these intermediates, noting that carbocations are planar with a bond angle of 120°, free radicals have unpaired electrons, and triplet carbenes are more stable than singlet carbenes. Additionally, it describes benzyne as an unstable aromatic intermediate derived from benzene with a carbon-carbon triple bond.

1. Reaction Intermediates
• Carbocation
• Carbanion
• Free radical
• Carbene
• Benzyne
Ms. Celeste Pereira
(Chemistry faculty)

2. REACTION INTERMEDIATES:
• Homolytic and heterolytic bond fission forms short
lived species called as reaction Intermediates.
• These short lived species are very reaction and are
quickly converted to more stable molecules.

3. • The carbon atom is Sp² Hybridised
• The carbocation have a planar structure.
• The bond angle between all the 3 sigma
bonds 120◦
a) Structure of Carbocation:

5. Stability of Carbocation

6. When the positively charged carbon atom is in conjugation with pi-bond, the
stability is greater because of increased delocalisation due to resonance and
because of it the +ve charge is spread over the molecule

10. Stability of Carbanion

11. 2.

12. Free Radicals
•Chemical Species having an unpaired electron is called
as free radical.
•It can be formed by homolytic bond fission.
Structure:
It could be planar or pyramidal
in structure, having an Odd
electron .

13. Formation of Free radical
1. Thermal Cleavage:
2. Potochemical Cleavage:

14. Stability
1)
2)
3)

15. Carbene

17. Stability of Carbene
Triplet carbene is more stable than the Singlet Carbene. Triplet
Carbene has lower energy because of the presence of 2
electrons in different orbitals leads to less electron-electron
repulsion.

18. Benzyne
 Benzyne are neutral intermediate derived from Benzene ring by removing
2 ortho Substituents.
 It is also called as 1,2 Didehydrobenzene
 Benzyne is very unstable molecule.
 Benzyne is represented by a single molecule with Carbon-carbon triple
bond
 Benzyne are aromatic in nature