Characteristic absorption frequencies in IR spectroscopy

Bond type Frequency(cm-1)
C-H alkane 2950 – 2850
C-H alkene 3080 – 3020
C-H aldehyde ~2900
C-H alkyne ~3300
alkyne triple bond 2250 – 2100 (s)
alkene double bond 1680 - 1620 (s)
carbonyl, ketone 1725 – 1700 (s)
carbonyl, aldehyde 1740 – 1720 (s)
carbonyl, ester 1750 – 1730 (s)
carbonyl, acid 1725 – 1700 (s)
carbonyl, amide 1690 – 1650 (s)
O-H, alcohol 3600 – 3200 (s, broad)
O-H, acid 3000 – 2500 (s, broad)
C-O, alcohol, ester, ether 1300 - 1000

Where,s = strong absorbance