Infrared spectroscopy, also known as IR spectroscopy or vibrational spectroscopy, is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. This technique is widely used in both organic and inorganic chemistry to determine the structures of compounds and identify them. An infrared spectrum is produced by an instrument called an infrared spectrometer, and it is a plot of measured infrared intensity versus wavelength or frequency of light. Molecules absorb specific frequencies of infrared light that are characteristic of their structure, and these absorptions are resonant frequencies that match the frequency of the bond or group that vibrates