Aldehydes and Ketones
Aldehydes and ketones contain a carbonyl group (>C=O), and are collectively called carbonyl compounds.
Some other examples of carbonyl compounds are : R-COOH (Carboxylic acid), R-COX (Acid halide), R-COOR' (Ester) etc.
In aldehydes, one end of the carbonyl group is attached to an alkyl (or aryl) group and the other is to a hydrogen atom.
Here R and Ar represent alkyl and aryl groups respectively. In condensed structural formulae, the carbonyl group of an aldehyde is represented as −CHO.
In ketones, both the ends of carbonyl group are attached to alkyl or aryl groups.
Important Points Regarding Carbonyl Groups
- The carbon atom of carbonyl group is sp2 hybridised and has trigonal planar structure.
- Since the electronegativity of oxygen is higher than that of carbon, the C=O bond is polar.
- The carbonyl group exhibits resonance :
Nomenclature of Aldehydes and Ketones
Rules for naming aldehydes and ketones are discussed in nomenclature of aldehydes and ketones. If you want to learn nomenclature from the very beginning, start from nomenclature introduction.