IR and Ultraviolet Spectroscopy

The sample may be a thin unsupported film (usually about 2 mm thick) a film evaporated on a nonabsorbing substrate such as NaCl a solution held in a nonabsorbing cell (often made of NaCl) a pressed, clear wafer of the material to be analyzed mixed with KBr powder or a mull of the material with a heavy paraffin oil held between NaCl flats. Other alkali and alkaline earth halides are used as substrates. Water and alcohols are not used as solvents generally, because they absorb strongly in the IR region and may corrode the substrates. 

Intramolecular hydrogen bonds Intermolecular hydrogen bonds Chelate compounds NH stretching vibrations Free NH 

C=C stretching vibrations Nonconjugated Conjugated CH bending vibrations CH3 CH3 

CH out-of-plane bending vibrations in substituted ethylenic systems -CH=CH2 -CH=CH-(cis) 

Source Cole, A. R. H., in K. W. Bentley (ed.) Elucidation of Structures by Physical and Chemical Methods, Part 1, Technique of Organic Chemistry. 1963. vol. XI, Wiley, New York, 33ff. Copyright Wiley-VCH Verlag GmbH Co. KGaA. 

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