Using IR spectroelectrochemistry, it is possible to characterise molecules according to their resistance, stiffness, and number of linkages. It also determines the structure of compounds, the characteristics of chemical bonds, the concentration of species during a reaction, the existence of compounds, etc. The electromagnetic radiation (EMR) known as infrared (IR), sometimes referred to as infrared light, has wavelengths that are longer than those of visible light. As a result, it is not apparent to the human eye. The wavelength range of infrared radiation is often thought to range from about 1 millimetre (300 GHz) to the notional red edge of the visible spectrum, which is around 700 nanometers (430 THz). Sometimes the terahertz radiation spectrum includes longer IR wavelengths (30 m to 100 m). Near-room temperature objects emit almost exclusively infrared radiation. The properties of infrared radiation, or IR, which is an electromagnetic radiation, are similar to both those of a wave and a particle called a photon. It propagates energy and momentum, exerts radiation pressure, and has other characteristics as well.