Typical IR Absorption Frequencies For Common Functional Groups

Bond Functional Group Frequency in cm-1 (Intensity*)
C-H Alkane 3000-2850 (s)
-CH3 1450 and 1375 (m)
-CH2- 1465 (m)
Alkene 3100-3000 (m), 1000-650 (s)
Aromatic 3100-3050 (s), 900-690 (s)
Alkyne (terminal) 3300 (s)
Aldehyde 2850 and 2750 (w)
C=C Alkene 1630 (w-m)
Aromatic 1600-1475 (w-m)
C-C Alkyne 2150-2100 (w-m)
C=O Aldehyde 1740-1720 (s)
Ketone 1725-1705 (s)
Carboxylic Acid 1730-1700 (s)
Ester 1750-1730 (s)
Amide 1670-1640 (s)
Anhydride 1810 and 1760 (s)
Acid Chloride 1800 (s)
C-O Alcohol, Ether, Ester, Carboxylic Acid, Anhydride 1300-1000 (s)
O-H Alcohol, Phenol
Free 3650-3600 (m)
Hydrogen-bonded 3500-3200 (m)
Carboxylic Acids 3300-2400 (m)
N-H Primary and Secondary Amine and Amide 3550-3060 (m-s); 1640-1550 (m-s)
C-N Amine 1250-1000 (m-s)
C=N Imine and Oxime 1690-1640 (w-s)
C=N Nitrile 2260-2240 (m)
N=O Nitro (R-NO2) 1550 and 1350 (s)
C-Cl Chloride 800-600 (s)

s = strong; m = medium; w = weak