What absorbs at 2953 cm⁻¹ in an FTIR spectrum?
A band near 2953 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 2953 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 | 23 | 21 | 1.0 |
| Methyl | 3 | 2 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 0.9 |
| Methoxy (OCH3) | 1 | 0 | 1.0 |
| Methacrylate | 1 | 0 | 1.0 |
| Acetate | 1 | 0 | 1.0 |
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 2953 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
“Moreover, a appeared due to C-H asymmetric stretching (aliphatic) at 2952.53 and 2920.71 cm(cid:3)1.”
Effect of used motor oil as a rejuvenator on crumb rubber modifier’s released components to asphalt binder DOI: 10.1177/1477760620918600 -
Alkyl C-H confidence 1.0
“@C-H 3006a (cis) Stretching 2953a 2 2989-2946 -C-H (CH3) Stretching (asym) 2924a 3 2946-2881 -C-H (CH2)”
Rapid evaluation of oxidised fatty acid concentration in virgin olive oil using Fourier-transform infrared spectroscopy and multiple linear regression DOI: 10.1016/j.foodchem.2010.06.054 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Transitions in unmodified and modified bitumen using FTIR spectroscopy DOI: 10.1617/s11527-018-1308-7 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Sikiti 等 - 2014 - Synthesis and characterization of molecularly impr DOI: 10.1186/2052-336X-12-82 -
Alkyl C-H confidence 1.0
“Spectrum of PNVP is provided in Figure 1, the absorption cm-1 2953.36 and 2892.91 peaks at are associated with the asymmetric and symmetric stretching vibrations of aliphatic methylene (-CH 2-) and methyl (-CH 3) coming from oligomer cm-1 a”
Electrochemical Sensor Based on Thioether Oligomer Poly(N-vinylpyrrolidone)-modified Gold Electrode for Bisphenol A Detection DOI: 10.1002/elan.201900060 -
Alkyl C-H confidence 1.0
“Also, two sharp absorption bands appeared at 2953 and 2874 that were assigned to the asymmetric and symmetric stretching vibrations for (C-H) bonds in the methylene group (-CH 2-).”
Enhanced Coating Protection of C-Steel Using Polystyrene Clay Nanocomposite Impregnated with Inhibitors DOI: 10.3390/polym15020372 -
Alkyl C-H confidence 1.0
“As can be seen, there is evidence of both lamine, for example, three defined peaks at 2853, 2919, and 2953cm-1 lysine and amide in the solutions (rather than just unreacted characteristic of symmetric and asymmetric -CH2 3360cm-1 are due to”
Alexander 等 - 2016 - Carboxylation and Decarboxylation of Aluminum Oxid DOI: 10.1155/2016/7950876 -
Alkyl C-H confidence 1.0
“The gas-phase spectra show FTIR bands at 2953 cm-1 cm-1 to C-H stretching vibration of the methyl group, 1737 due to C=O stretching and related to C-H stretching vibration of the methyl group, 1737 cm-1 due to C=O stretching cm-1 697 relate”
Caliskan 等 - 2022 - Investigation of the Side Chain Effect on Gas and DOI: 10.3390/polym14010119
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