Infrared (IR) spectroscopy is a technique that is used to identify and analyze the molecular structure of a substance. In order to prepare a sample for IR spectroscopy, it is often necessary to dissolve the sample in a solvent. The choice of solvent depends on the nature of the sample and the vibrational modes of the bonds in the molecule that are being studied. In general, it is best to use a solvent that does not absorb infrared light at the wavelengths of interest. This is because the absorption of the solvent can interfere with the measurement of the absorption of the sample. Common solvents that are used for IR spectroscopy include liquid hydrocarbons (such as hexane, cyclohexane, and toluene), alcohols (such as methanol, ethanol, and isopropanol), and water. In some cases, it may be necessary to use a more specialized solvent, such as dimethylformamide (DMF) or dimethylsulfoxide (DMSO), depending on the nature of the sample. It is important to note that the choice of solvent can affect the absorption spectrum of the sample. In some cases, the presence of a solvent can alter the vibrational modes of the bonds in the molecule, which can affect the interpretation of the IR spectrum. Therefore, it is important to carefully consider the choice of solvent when preparing a sample for IR spectroscopy.