| Atoms | mode | type | Region (cm-1) |
|---|---|---|---|
| O-H | stretch | free | 3600-3650 |
| H-bonded | 3200-3500 | ||
| N-H | stretch | sym | 3100-3500 |
| asym | |||
| C-H | stretch | alkynes | 3300 |
| aromatics | 3050-3150 | ||
| alkenes | 3000-3100 | ||
| alkanes | 2850-3000 | ||
| aldehydes | 2700-2900 | ||
| C=N | nitriles | 2240-2260 | |
| C=C | alkynes | 2100-2250 | |
| X=C=Y | allenes | 1950-2270 | |
| C=O | anhydride | 1760 & 1810 | |
| acid chloride | 1800 | ||
| ester | 1730-1750 | ||
| aldehyde | 1720-1740 | ||
| ketone | 1705-1725 | ||
| carboxylic acid | 1700-1725 | ||
| amide | 1640-1670 | ||
| C=N | imine | 1640-1690 | |
| C=C | alkene | 1600-1680 | |
| aromatic | 1475 & 1600 | ||
| O-H | |||
| N-H | bend | 1550-1640 | |
| C-H | bend | -CH2- | 1465 |
| -CH3 | 1375 & 1450 | ||
| C-N | amines | 1000-1350 | |
| C-O | alcohols | 1000-1300 | |
| C-H | out-of-plane bend | alkenes | 650-1000 |
| aromatics | 690-900 |