What absorbs at 2654 cm⁻¹ in an FTIR spectrum?
A band near 2654 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 2 cited sources
Quick answer
A band near 2654 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
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 2 | 2 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative 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 2654 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
-
Ring structure confidence 1.0
“Besides, after the formation of PPy, the new cm-1 peaks that appeared at 2654 ± 5 and 2424 ± 5 in PPy/rGO, and Pd/PPy/rGO correspond to the PPy ring deformation or =C-H plane pending and C-H plane pending, respectively.”
Fabrication of Palladium Nanoparticles Anchored Polypyrrole Functionalized Reduced Graphene oxide Nanocomposite for Antibiofilm Associated Orthopedic Tissue Engineering DOI: 10.1016/j.apsusc.2020.145403 -
confidence 1.0
“Fourier Transform Spectroscopy BAB in the pure drug spectrum exhibits the characteristics peaks at 3345 cm-1, 3012 cm-1, 2654 cm-1, and 2322 cm-1 for the N-H stretching, aromatic = C-H stretching, -C-H”
Design and Characterization of Baricitinib Incorporated PLA 3D Printed Pills by Fused Deposition Modeling: An Oral Pill for Treating Alopecia Areata DOI: 10.3390/polym15081825
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