What absorbs at 1622 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1622 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.

Possible functional-group assignments

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

Possible materials

Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.

Spectrum logic

This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1622 cm⁻¹ is usually not enough for material identification by itself.

Real-world usage

This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.

Common mistakes

• Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
• Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
• Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.

Verification advice

When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.

Literature behind these assignments

• Hydroxyl (O-H) confidence 1.0

  “for the fragment and 1578 and 1622 cm-1 (CI), hydroxyl (HI), and carbon-oxygen (COI) indexes representative of the degree of Finally, new peaks at 1653 cm-1 also appear in the IR spectrum of UV-aged PS fragdegradation of particles.”

  Campanale 等 - 2023 - Fourier Transform Infrared Spectroscopy to Assess DOI: 10.3390/polym15040911
• Hydroxyl (O-H) confidence 1.0

  “= υ chain were clearly visible at 2915, 2876, and 1370 In Figure 1B, for CuO nanoparnanoparticles, two peaks, one at 3418 cm-1 of the O-H stretching and the other at 1622 cm-1 cm-1 cm-1 ticles, two peaks, one at 3418 of the O-H stretching a”

  Chitosan Capped Copper Oxide Nanocomposite: Efficient, Recyclable, Heterogeneous Base Catalyst for Synthesis of Nitroolefins DOI: 10.3390/catal12090964
• Alkene (C=C) confidence 1.0

  “In boiler ash aromatic ring, C=O stretching on the ketones, C=C cm-1, stretching of hemicellulose, and C=C stretching of vinylidene alkenes appeared at 777.60 1621.90 cm-1, cm-1, cm-1, 1064.25 and 790.10 respectively [18].”

  Hidayani 等 - 2022 - Acoustic and Mechanical Properties of Polystyrene DOI: 10.37358/Mat.Plast.1964
• Acetate confidence 1.0

  “In the fly ash, it can be seen that the absorption at 1621.90 cm-1 presented C=O stretching on the ketone.”

  Preparation and Characterization of Sound-Absorbent Based on Polystyrene Reinforced Primary Sludge and Fly Ash from Pulp Mill DOI: 10.14716/ijtech.v14i3.5131
• Aromatic ring confidence 1.0

  “present between 2940 and 2915 and 2870-2850 Although present, the aromatic C=O stretching band is weak, whereas the aromatic C=C stretching band peaking cm-1 at 1622 is relatively strong.”

  Mathews 和 Singh - 2016 - Characterization of solid bitumen from Panandhro l DOI: 10.18520/cs/v111/i11/1842-1846
• C=n confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Uptake of Metal Ions (Co(II) and Ni(II)) by Silica-Salicylaldehyde Derived from Rice Husks DOI: 10.1007/s10904-019-01379-7
• Alkyl C-H confidence 1.0

  “and 1622 C-H stretching of the -CH 2groups and secondary amines) (Socrates, The assignments of the above peaks are presented in at cm-1 1997;”

  Tarantilis 等 - 2012 - Monitoring of royal jelly protein degradation duri DOI: 10.3896/IBRA.1.51.2.07
• C c single bond confidence 1.0

  “Similarly, the second branch of the peak, 1584.42 cm-1 cm-1 is attributed to two simulation peaks of 1621.69 and 1624.96 and once again motions are same in these peaks too, active C-C stretching in the USC rings in different fashions.”

  Raman spectroscopy of Bisphenol ‘S’ and its analogy with Bisphenol ‘A’ uncovered with a dimensionality reduction technique DOI: 10.1016/j.molstruc.2018.08.025