Basic IR Spectra Interpretation

Once the spectrum is obtained, the question remains as to how to interpret it. We stated previously (Section 8.6) that IR spectra are characterized by rather sharp absorption bands (peaks) and each such peak is characteristic of a particular covalent bond in a molecule in the path of the light. Thus for qualitative analysis (identification and purity characterization), the analyst correlates the location (the wavenumber), the shape, and the relative intensity of a given peak observed in a spectrum with a particular type of bond. 

FIGURE 8.29 The IR spectrum of an alcohol with no benzene rings. 

FIGURE 8.30 The IR spectrum of a compound with a carbonyl group and no benzene ring. 

TABLE 8.1 Some Easily Recognizable IR Absorption Patterns 

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