Bond Type

 Specific Context

n, cm^-1

 Stretching Frequencies

 C-H

C_sp3-H

2800-3000

C_sp2-H

3000-3100

C_sp-H

3300

C-C

C-C

1150-1250

C=C

1600-1670

CºC

2100-2260

C-N

C-N

1030-1230

C=N

1640-1690

CºN

2210-2260

C-O

C-O

1020-1275

C=O

1650-1800

C-X

C-F

1000-1350

C-Cl

800-850

C-Br

500-680

C-I

200-500

N-H

RNH₂, R₂NH

3400-3500 (two)

RNH₃⁺, R₂NH₂⁺, R₃NH⁺

2250-3000

RCONH₂, RCONHR'

3400-3500

O-H

ROH

3610-3640 (free)

3200-3400 (H-bonded)

RCO₂H

2500-3000

N-O

RNO₂

1350,1560

RONO₂

1620-1640, 1270-1285

 RN=O

1500-1600

RO-N=O

1610-1680 (two), 750-815

C=N-OH

930-960

R₃N-O⁺

950-970

S-O

R₂SO

1040-1060

R₂S(=O)O

1120-1160

R-S(=O)₂-OR'

1330-1420, 1145-1200

Cumulated systems

C=C=C

1950

C=C=O

2150

R₂C=N=N

2090-3100

RN=C=O

2250-2275

RN=N=N

2120-2160

Out-of-plane bending vibrations

Alkynes

CºC-H

600-700

Alkenes

RCH=CH₂

910, 990

R₂C=CH₂

890

trans-RCH=CHR

970

cis-RCH=CHR

725, 675

R₂C=CHR

790-840

Aromatic

mono-

730-770, 690-710 (two)

 o-

735-770

m-

750-810, 690-710 (two)

p-

810-840

1,2,3-

760-780, 705-745 (two)

1,3,5-

810-865, 675-730 (two)

1,2,4-

805-825, 870, 885 (two)

1,2,3,4-

800-810

1,2,4,5-

855-870

1,2,3,5

840-850

penta-

870

Carbonyl Stretching Frequencies

Aldehydes

RCHO

1725

C=CCHO

1685

ArCHO

1700

Ketones

R₂C=O

1715

C=C-C=O

1675

Ar-C=O

1690

four-membered cyclic

1780

five-membered cyclic

1745

six-membered cyclic

1715

Carboxylic Acids

RCOOH

1710 (dimer

C=C-COOH

1690 (dimer)

RCO₂^-

1550-1610, 1400 (two)

Esters

RCOOR

1735

 C=C-COOR

1720

ArCOOR

1720

g-lactone

1770

d-lactone

1735

Amides

RCONH₂

1650 (associated)

RCONHR'

1655 (associated)

RCONR₂'

1650

b-lactam

1745

g-lactam

1700

d-lactam

1640

Acid anhydrides

1820, 1760 (two)

Acyl halides

1800