IR spectroscopy is a powerful analytical technique used to identify chemical substances based on their absorption of infrared radiation. It provides information about molecular structure without decomposition. The IR region extends from 0.8-2.5 microns. IR spectroscopy works by detecting the vibrational and rotational frequencies of molecules when IR radiation is passed through a sample. The resulting absorption spectrum is unique to a compound's molecular structure and functional groups. Common instrumentation includes an IR source, monochromator, sample cell, detector, and recorder. Applications include determining compound purity and structure, and detecting impurities in industrial samples.