Explain the structure of carbonyl functional group
Structure of the carbonyl functional group:
1) In aldehydes and ketones, the carbonyl carbon atom is sp2 hybridised and bonded to three other atoms by sigma (σ) bonds. One of the sigma bond is formed with oxygen atom and other two with hydrogen and/or with carbon atoms. Thus, the carbonyl carbon and the three atoms attached to it lie in the same plane.
2) The remaining unhybridized 2p orbital of carbon overlaps with 2p orbital of oxygen to form pi (π) bond. This results in double bond between carbon and oxygen.
3) The bond angles are approximately 120° as expected of a trigonal coplanar
structure as shown in the figure.
The oxygen atom carries two lone pairs of electrons. The π-electron cloud lies above and below the plane of the rest of the atoms.