Infrared Absorption Bands

Introduction

IR absorption spectroscopy uses mid-infrared light (2.5 - 50 µm, 4000 - 200 cm^-1) to detect specific types of chemical bonds in a sample for identification of organic and organometallic molecules.

Table of characteristic IR bands

Group    Bond    Appox. Energy (cm-1)

hydroxyl  O-H   3610-3640

amines    N-H   3300-3500

aromatic rings  C-H   3000-3100

alkenes   C-H   3020-3080

alkanes   C-H   2850-2960

nitriles  C=-N    2210-2260

carbonyl  C=O   1650-1750

amines    C-N   1180-1360