Functional Group Region

4000-1400 cm

Fingerprint Region

<1400 cm

Hydrogen Region

4000-2400 cm

Sp3 hybridized C-H stretch

~2990-2860 cm

Sp2 hybridized C-H stretch

alkenyl- ~3150-3010 cm

aromatic- ~3100-3010 cm

Sp hybridized C-H stretch

~3450-3350 cm

weak to moderate, sharp

Formyl C-H stretch

2 bands

~2800 cm

~2700 cm

O-H stretch (alcohol/phenol)

alcohol/phenol: ~3400-3250 cm

strong, broad

Alcoholic O-H stretch without hydrogen bonding

 ~3600-3500 cm

strong, sharp

- alcohol needs to be in gas form or extremely dilute in order for this to occur.

N-H stretch (amine)

 2 bands

~3450-3300 cm

moderate, semi-broad to sharp

O-H stretch (carboxylic acid)

carboxylic acid: ~3000 cm

strong, broad

N-H stretch (amide)

~3450-3300 cm

moderate to strong, sharp 

Triple Bond Region

2400-2100 cm 

Carbon-Carbon triple bond

terminal alkyne: ~2190-2100 cm

weak to moderate, sharp

internal alkyne: ~2200-2100 cm

very weak or absent

only is shown if alkyl groups on either side of the internal alkyne are different

C-N triple bond (nitrile)

~2300-2200 cm

moderate to strong, semi-sharp to sharp

Double Bond Region

2100-1400 cm

N=O (nitro)

2 bands

~1550 cm

~1450 cm

N=O (nitroso)

~1500 cm

moderate to strong, semi-sharp

C=C (alkene)

normal: ~1670-1640 cm

conjugated: 2 bands

                       ~1660 cm

                       ~1630 cm

C=C (aromatic)

2 bands

~1600 cm

~1500 cm

weak to moderate, semi-sharp

C=O (aldehyde)

normal: ~1720 cm

conjugated: ~1700-1690 cm

C=O (ketone)

normal: ~1710 cm

conjugated: ~1690-1680 cm

C=O (carboxylic acid)

normal: ~1710

conjugated: ~1690-1680 cm

C=O (ester)

~1735 cm

C=O (anhydride)

2 bands

~1830 cm

~1770 cm

C=O (acid halide)

Halide: Br, Cl, I

~1780-1760 cm

C=O (amides)

3 types:

primary- two hydrogens bonded to N

secondary- one hydrogen and alkyl bonded to N

tertiary- two alkyl groups bonded to N (no N-H stretch shown)

 ~1680-1660 cm