Aldehyde and Ketone IR Peaks Explained

Infrared spectroscopy helps identify bonds and functional groups in aldehydes and ketones. It is also called vibrational spectroscopy because it measures bond vibrations. In these molecules, the carbonyl group, or C=O bond, gives an absorption around 1710 cm -1 .

Aldehydes and ketones do not alwa...

The IR spectrum of a simple aldehyde shows a strong carbonyl stretch around 1725 cm^-1. In a simple ketone, the C=O stretching absorption shifts to a lower frequency.

Aldehydes also give two weak bands at higher wavenumbers, characteristic of the aldehydic C–H bond stretch.

Conjugating the carbonyl group with a double bon...