No Group frequency, wavenumber (cm–1)/Assignment | Functional Class |
---|---|
1 <1000 cm–1 [750–720 Methylene–(CH 2 )n–rocking, 970–960 trans-C–H out-of-plane bend; 700 (broad) cis–C–H out-of-plane bend] | Isoprenoids |
2 997–1130 cm–1 [1050–990 Aliphatic phosphates (P–O–C stretch)] | mono–, oligo– carbohydrates |
3 1150–1270 cm–1 [1210–1150 Tertiary amine, CN stretch] | acid or ester |
4 1300–1450 cm–1 [1350–1260 Primary or secondary, OH, in-plane bend 1410–1310 Phenol or tertiary alcohol, OH bend] | Amide, phenyl groups |
5 1500–1600 cm–1 [1610–1550/1420–1300 Carboxylate (carboxylic acid salt); 1680–1630 Amide] | amino acids |
6 1600–1760 cm–1 [1615–1580 Aromatic ring stretch] | Aldehydes, cetones, esters |
7 2800–2900 cm–1 [2970–2950/2880–2860 Methyl C–H asym./sym. Stretch] | lipids, metoxy derivatives (cis double bonds) |
8 3000–3600 cm–1 [3095–3075 Terminal (vinyl) C–H stretch; 3040–3010 3095–3075 vinylidene C–H; Stretch 3040–3010 Medial, cis–or trans–C–H; Stretch, 3570–3200 (broad) Hydroxy group, H-bonded; OH stretch 3400–3200 Normal polymeric OH Stretch 3550–3450 Dimeric OH stretch; 3570–3540 Internally bonded OH stretch] | water, alcohols, phenols, carbohydrates, peroxides |