What absorbs at 2962 cm⁻¹ in an FTIR spectrum?
A band near 2962 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 8 cited sources
Quick answer
A band near 2962 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 | 36 | 32 | 1.0 |
| Methyl | 11 | 10 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Lipid | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| polyester | 2962, 1700, 1250 | Alkyl C-H, Methacrylate, Acetate | 1 |
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 2962 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
-
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Bougharouat 等 - 2011 - Plasma polymerization of TEOS for QCM-based VOC va DOI: 10.1051/epjap/2011110144 -
Alkyl C-H confidence 1.0
“Finally, the vibrations 2 cm-1 2962 and 2874 are assigned to C-H antisymmetric and symmetric stretching of methyl groups [31].”
Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan DOI: 10.1016/j.vibspec.2019.04.005 -
Alkyl C-H confidence 1.0
“Two very-low-intensity bling agglomerates of sizes ~ 0.2-0.4 as seen in the cm(cid:1)1 peaks at ~ 2962 and 2923 indicate C-H stretching SEM micrographs.”
Chowdhury 等 - 2004 - Novel electrodeposition route for the synthesis of DOI: 10.1016/j.matlet.2004.05.079 -
Alkyl C-H confidence 1.0
“Schiff base ACCEPTED MANUSCRIPT 3.2 FTIR Spectral studies The Infra-red spectroscopic studies of 4EMP show three peaks around 2962, 2929 and 2871cm-1 which are characteristic of alkane homologues due to the CH 2CH functional 3”
Synthesis, crystal structures, quantum chemical studies and corrosion inhibition potentials of 4-(((4-ethylphenyl)imino)methyl)phenol and (E)-4-((naphthalen-2-ylimino) methyl) phenol Schiff bases DOI: 10.1016/j.molstruc.2017.06.104 -
Alkyl C-H confidence 1.0
“asymmetric stretching was newly observed at 2961.8 With an 4 αN s a � � 3� � ¼ (4) cm(cid:0) S SO2(cid:0) NO(cid:0) 1 ⋅ 2922-2944 increase of alkyl chain length, new peaks at and 4 s”
Kang 和 Kim - 2020 - Synthesis of quaternized mesoporous silica SBA-15 DOI: 10.1016/j.micromeso.2019.109967 -
Alkyl C-H confidence 1.0
“stretching (2962, 2915 and 2848 In the PBSeT samples, the C-H bond signals of the PBSe”
Synthesis, Characterization and Properties of Biodegradable Poly(Butylene Sebacate-Co-terephthalate) DOI: 10.3390/polym12102389 -
Lipid confidence 1.0
“cm-1 α (related to RNA), 1651 (amide I helix structure), significant peak displacement were 1120 cm-1 cm-1 2851 (related to lipids - CH stretching) and 2962 (related to lipids - CH stretching).”
Mostaco-Guidolin 等 - 2010 - Molecular and chemical characterization by Fourier DOI: 10.3233/SPE-2010-0466 -
Alkyl C-H confidence 1.0
“The increase of the IR peak at 2962 due to the asymmetrical C-H stretch mode in CH ligands and the 3 cm-1 appearance of a weak peak around 710 due to wagging N-”
Park 等 - 2016 - In-situ Monitoring System Equipped with FT-IR and DOI: 10.1149/07506.0123ecst
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