C=O stretchings
Carbonyl function
Very intense and a little broad in the presence of hydrogen bonds
Most typical band: νC=O from 1800 to 1600 cm-1
![Illustration of a C=O bond. The upper bond is red, with arrows moving away. The lower bond is black, with arrows approaching.](/resources/images/fiches/bases/ir-raman/raman35.png)
Strategy
- Ketones:
![Illustration ketones : V asym, a C-C bond approaching, a C-C bond moving away, a C=O bond](/resources/images/fiches/bases/ir-raman/en/raman36.png)
- Aldehydes:
- Esters: 3 intense and rather broad bands
νC=O = 1700 cm-1
νC-C-O = 1200 cm-1
νO-C-C = 1100 cm-1
νC-C-O = 1200 cm-1
νO-C-C = 1100 cm-1
![Illustrations Esters : V asym C-C-O, and V O-C-C](/resources/images/fiches/bases/ir-raman/en/raman37.png)
- Carboxylic acids:
- Carboxylates: 2 intense bands
νsym C=O = 1450-1360 cm-1