Typical Infrared (IR) frequencies of common functional groups

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Carbonyl Absorptions n (cm-1)

Acid chlorides ~ 1790; Esters ~ 1740;   Aldehydes ~ 1720; Ketones ~ 1710;     Acids ~ 1700;    Amides ~ 1650