What absorbs at 2880 cm⁻¹ in an FTIR spectrum?
A band near 2880 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 2880 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 | 33 | 29 | 1.0 |
| Hydroxyl (O-H) | 6 | 6 | 1.0 |
| Methacrylate | 6 | 5 | 1.0 |
| Acetate | 6 | 5 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methyl | 3 | 3 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Ketone | 2 | 1 | 1.0 |
| Ester | 2 | 1 | 1.0 |
| Carboxyl (COOH) | 2 | 1 | 1.0 |
| Carbonyl (C=O) | 2 | 1 | 1.0 |
| Amide | 2 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| N h | 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 |
|---|---|---|---|
| chitosan | 2880, 1650, 1655 | Alkyl C-H, Acetate, Methacrylate | 1 |
| methane | 2880, 1740, 1400 | Alkyl C-H, Hydroxyl (O-H), Methacrylate | 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 2880 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
“Vibrational bands at 2935 cm-1 cm-1 and 2880 referred to a C-H stretching, 1478 to the CH bending of an alkyl”
Can 等 - 2023 - Choline Chloride-Based Deep Eutectic Solvent-Treat DOI: 10.3390/f14030569 -
Alkyl C-H confidence 1.0
“The peak at 2880.33 is the symmetric stretching mode of all 2 44 cm-1 N-alkyl chains.”
Structural Dependence and Spectroscopic Evidence of Methane Dissolution in Ionic Liquids DOI: 10.1021/acs.jpcb.8b03178 -
Alkyl C-H confidence 1.0
“Another significant cm-1 change was observed at the wavenumber of 2880 ascribing C-H and O-H stretching.”
Jaiswal 和 Dhayal - 2020 - Preparation of 2D coatings of functionally graded DOI: 10.1016/j.matchemphys.2020.122663 -
Alkyl C-H confidence 1.0
“The ∼2880cm-1 ∼1400cm-1 ∼2350 ∼1300 Among these peaks, those at and peaks at and are show reasonable agreement C-H known to correspond to CO with those in the experiment.”
Kurokawa 等 - 2016 - Possible formation of one-dimensional chains of C2 DOI: 10.7567/APEX.9.049201 -
Acetate confidence 1.0
“The FTIR band at 2930 are attributed tothe CH2 symmetric and antisymmetric cm(cid:1)1 cm(cid:1)1 940,1220,1167,1303,1330, 841, 998, 900, 808,1100, and 973 stretching modes, while the bands near 2880 and 2950 are were corresponding to the he”
The influence of vulcanizer on the crystal transform of iPP during reactive extrusion process DOI: 10.1016/j.polymdegradstab.2016.02.001 -
Alkyl C-H confidence 1.0
“The absorption peak at about 2880 is associated with the stretching vibration of C-H, arising from the produced organic matter in the incomplete combustion process.”
Effect of In3+ substitution on structural and magnetic properties of Ni ferrite nanoparticles DOI: 10.1016/j.physb.2016.09.031 -
Alkyl C-H confidence 1.0
“The had an alcoholic 2 cm-1 "tequila blanco" and the peak at 2880 was related to the C-H strength of 35% alcohol vol.”
Mondragon-Cortez 等 - 2022 - Application of Fourier transform infrared spectros DOI: 10.24275/rmiq/Alim2806 -
Alkyl C-H confidence 1.0
“The schematic of the benzene, the initially two prominent peaks at 2880 and 2945 [BMIM]+ structure and the numbering system for cation is cm-1 due to the CH (ss) and CH (FR) of the neat ssp spectrum 3”
GasLiquid Interface of Hydrophobic and Hydrophilic Room-Temperature Ionic Liquids and Benzene: Sum Frequency Generation and Surface Tension Studies DOI: 10.1021/jp803177w
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