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aldehyde/ketone saturated aliph./cyclic 6-membered 1720 α,β-unsaturated 1685 aromatic ketones 1685 cyclic 5-membered 1750 cyclic 4-membered 1775 aldehydes 1725 influenced by conjugation (as with ketones) carboxylic acids/derivates saturated carboxylic acids 1710 unsat./aromatic carb. acids 1680–1690 esters and lactones: 1735
Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes such as formaldehyde and acetaldehyde are soluble in water, and the volatile aldehydes have pungent odors. Aldehydes can be identified by spectroscopic methods. Using IR spectroscopy, they display a strong ν CO band near 1700 cm −1.
The FT-IR spectra were recorded using a Nicolet 170SX or a JASCO FT/IR-410 spectrometer. For spectra recorded in the Nicolet spectrometer, the data were stored at intervals of 0.5 cm −1 in the 4,000 – 2,000 cm −1 region and of 0.25 cm −1 in the 2,000 – 400 cm −1 region and the spectral resolution was 0.25 cm −1.
Infrared spectroscopy (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. It can be used to characterize new materials or identify ...
Spectrochemistry is the application of spectroscopy in several fields of chemistry. It includes analysis of spectra in chemical terms, and use of spectra to derive the structure of chemical compounds, and also to qualitatively and quantitively analyze their presence in the sample.
A Fermi resonance is the shifting of the energies and intensities of absorption bands in an infrared or Raman spectrum. It is a consequence of quantum-mechanical wavefunction mixing. [ 1 ] The phenomenon was first explained by the Italian physicist Enrico Fermi .
Many commercial instruments for UV/vis spectroscopy are capable of recording spectra in the NIR range (to perhaps ~900 nm). In the same way, the range of some mid-IR instruments may extend into the NIR. In these instruments, the detector used for the NIR wavelengths is often the same detector used for the instrument's "main" range of interest.
A common spectroscopic method for analysis is Fourier transform infrared spectroscopy (FTIR), where chemical bonds can be detected through their characteristic infrared absorption frequencies or wavelengths. These absorption characteristics make infrared analyzers an invaluable tool in geoscience, environmental science, and atmospheric science.