Carbonyl groups define two related families of organic compounds: the aldehydes and the ketones. The carbonyl group is ubiquitous in biological compounds. It is found in carbohydrates, fats, proteins, nucleic acids, hormones, and vitamins—organic compounds critical to living systems.

Functional group Carbonyl (Aldehydes and Ketones)

Aldehydes and ketones are compounds that contain a carbonyl functional group. The carbonyl carbon in an aldehyde has at least one hydrogen attached to it and the carbonyl carbon in a ketone is attached to only alkyl or aromatic group ( no hydrogen).

An Aldehyde is a carbonyl containing organic compound in which the carbonyl carbon atom has at least one hydrogen atom directly attached to it. The remaining group attached to the carbonyl carbon atom can be hydrogen, an alkyl group (R), a cycloalkyl group or an aryl group.

A primary Carbon is part of the Carbonyl group (Carbon bound to Oxygen by a double bond) in aldehydes. This Carbon is joined to Hydrogen and Alkyl radical or Aryl group (aromatic ring radical).

A ketone is a carbonyl-containing organic compound in which the carbonyl carbon atom has two other carbon atoms directly attached to it. The groups containing these bonded carbon atoms may be alkyl, cycloalkyl or aryl.

A secondary Carbon is part of the Carbonyl group (Carbon bound to Oxygen by a double bond) in ketones. This Carbon can be joined to Alkyl radical or Aryl group (aromatic ring radical).

In condensed formulas, we use CHO to identify an aldehyde rather than COH, which might be confused with an alcohol. This follows the general rule that in condensed structural formulas H comes after the atom it is attached to (usually C, N, or O).

Condensed representation of Carbonyl group in aldehydes and ketones.

The carbon-to-oxygen double bond is not shown but understood to be present

Quizzes

Practice Quiz: Module 13 Unit 1

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