CHEM 281 Study Guide - Final Guide: Phenols, Bond Length, The Vibrations
11 Jul 2018
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Document Summary
Infrared spectroscopy technique that give evidence for the presence of various functional groups / determine its solubility in common solvents and its melting and boiling point. Depends on the interaction of molecules or atoms with electromagnetic radiation. Causes atoms and groups of atoms of organic compounds to vibrate with increased amplitude about the covalent bonds that connect them. The vibrations are quantized, and as they occur, the compounds absorb ir energy in particular regions of the ir portion of the spectrum. Operates by passing a beam of ir radiation through a sample and comparing the radiation transmitted through the sample with that transmitted in the absence of the sample. The larger the wavenumber (1/ ), the higher is the frequency of the wave, and correspondingly the higher frequency of the bond absorption. Covalently bonded atoms have only particular vibrational energy levels. Stretching vibration: symmetric stretching ((cid:553)(cid:554)), asymmetric stretching ((cid:555)(cid:554)), an in-plane bending vibration (scissoring), an out-of-plane bending vibration (twisting)
