karbonylstretch

The term "karbonylstretch" is not a recognized scientific or technical term in standard chemistry or physics literature. It appears to be a neologism or a misspelling. However, if interpreted as a combination of "karbonyl" (likely a misspelling of carbonyl) and "stretch," it could refer to the stretching vibration of a carbonyl group (C=O) within a molecule, as observed in spectroscopy.

A carbonyl group is a functional group with the chemical formula C=O. This double bond is polar due to the difference in electronegativity between carbon and oxygen. The stretching vibration of this bond is a fundamental spectroscopic signature. In infrared (IR) spectroscopy, the carbonyl stretch typically appears in a characteristic region, usually between 1650 and 1850 wavenumbers. The exact position of this absorption band is sensitive to the molecular environment of the carbonyl group, including conjugation, inductive effects, and ring strain. For instance, a conjugated carbonyl group will generally absorb at a lower wavenumber than an isolated one. The intensity of the carbonyl stretch in IR spectroscopy is also typically strong due to the significant change in dipole moment during the vibration. Raman spectroscopy can also detect carbonyl stretching vibrations, though their intensity and prominence can vary compared to IR spectroscopy.