Functional Group

Absorption Location (cm−1)

Absorption Intensity

Alkane (C-H)

2850 - 2975

Medium to strong

Alcohol (O-H)

3400 - 3700

Strong, broad

Alkene (C=C)

1640 - 1680

Weak to medium

(C=C-H)

3020 - 3100

Medium

Alkyne

(C≡C)

2100 - 2250

Medium

(C≡C-H)

3300

Strong

Nitrile (C≡N)

Aromatics

1650 - 2000

Weak

Amines (N-H)

3300 - 3350

Medium

Carbonyls (C=O)

Strong

Aldehyde (CHO)

1720 - 1740

Ketone (RCOR)

1715

Ester (RCOOR)

1735 - 1750

Acid (RCOOH)

1700 - 1725