8. Infrared Spectroscopy Infrared (IR) Spectroscopy is an analytical method that measures the absorbance of a select band of electromagnetic radiation by a sample. The wavelength of radiation that is absorbed is characteristic of different types of chemical bonds. The graphical representation of the absorption of the electromagnetic radiation by the sample makes an IR spectrum. Organic chemists use infrared spectroscopy as a means of identifying various functional groups within compounds. This information is used to determine the structure of compounds. IR is usually used in combination with other techniques, especially nuclear magnetic resonance (NMR) spectroscopy. In this class you will learn how to interpret an IR spectrum and how to