What absorbs at 2893 cm⁻¹ in an FTIR spectrum?
A band near 2893 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 2893 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 | 7 | 7 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydrogen bond | 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 |
|---|---|---|---|
| cellulose | 2893, 1735, 1650 | Alkyl C-H, Hydroxyl (O-H) | 2 |
| bacterial cellulose | 2893, 1050, 1631 | Hydroxyl (O-H), Alkyl C-H | 1 |
| Chitosan | 2893, 1650, 1655 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| cellulose nanocrystals | 2893, 1110, 1640 | Alkyl C-H, Hydroxyl (O-H) | 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 2893 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
“WP, cm-1 O-H stretching, and the peak at 2893 is the characthe prominent peak of modified wood was merged in the teristic band for C-H stretching.”
Awal 等 - 2012 - Thermal analysis and spectroscopic studies of elec DOI: 10.1007/s10973-011-1875-0 -
Alkyl C-H confidence 1.0
“The band at 2893 is assigned to the CH 2-S asymmetric stretching mode of vibration.”
Crystal Growth, Spectral, Optical, Laser damage, Photoconductivity and Dielectric Properties of Semiorganic L-cystine hydrochloride Single Crystal DOI: 10.1016/j.saa.2015.06.113 -
Hydroxyl (O-H) confidence 1.0
“For the initial membrane (Figure 6), the absorption bands at around 3487, 2941 and 2893 cm-1 are characteristic of stretching vibrations of the -OH, -CH 2, and”
Rupiasih 等 - 2018 - Study on Transport Properties of Chitosan Membrane DOI: 10.5614/j.math.fund.sci.2018.50.2.6 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Plasma surface-modification of cellulose nanocrystals: a green alternative towards mechanical reinforcement of ABS DOI: 10.1039/c9ra02451d -
Hydrogen bond confidence 1.0
“The band at 2893 cm-1 cm-1 is due to carbon-hydrogen bond (C-H) stretching.”
Jafirin 等 - 2013 - Composite Polymer Electrolytes based on MG49 and C DOI: 10.1063/1.4858757 -
Alkyl C-H confidence 1.0
“The bands at 2893 and of acetic acid-hydrogen peroxide treated fiber cell showed are characteristics of C-H stretching and -CH2 bending, highlyroughnesswithreducedmicrovoidsfromparenchyma 900cm-1 respectively.”
Liew 等 - 2015 - Synthesis and Characterization of Cellulose from G DOI: 10.1155/2015/212158 -
Alkyl C-H confidence 1.0
“cm-1, thermal degradation, like depolymerization and decomposition of groups at 2893 the band corresponding to CH asymmetric 2 cm-1(Oh cm-1 dehydrocellulose into gases (water, carbon monoxide and carbon stretching at 2854 et al., 2005) and”
Komagataeibacter rhaeticus as an alternative bacteria for cellulose production DOI: 10.1016/j.carbpol.2016.06.049 -
Acetate confidence 1.0
“The spectrum of CoAl 2O nanocomposites calcined at 1100 °C is also shown by FT-IR, with 4 cm-1 cm-1 3sharp bands between 2893 and 3335 (C-O and C-C vibration) and at 1523 (NO vibration).”
Synthesis and electrochemical performance of α-Al2O3 and M-Al2O4 spinel nanocomposites in hybrid quantum dot-sensitized solar cells DOI: 10.1038/s41598-022-21186-4
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