Peak No.

Wave number (cm⁻¹)

Tentative assignment

1

1368

Amide-III N-H in solid state also for water absorption and H-bonding

2

1575

${\text{RCO}}_2^{-}$ , N-H bending for secondary Amide-II in solid state

3

1688

Amide-I

4 and 5

2900 - 3100

Aliphatic and Aromatic C-H stretching

6

3100 - 3600

Broad band for O-H stretching N-H stretching and H-bonding