What absorbs at 2916 cm⁻¹ in an FTIR spectrum?
A band near 2916 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 2916 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 | 51 | 47 | 1.0 |
| Hydroxyl (O-H) | 6 | 6 | 1.0 |
| N h | 5 | 4 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Aldehyde (CHO) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Ammonium | 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 |
| Hydrogen bond | 1 | 0 | 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 | 2916, 1735, 1650 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| hemicellulose | 2916, 1730, 897 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| polyethylene | 2916, 1737, 1720 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| lignin | 2916, 1035, 1510 | 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 2916 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
“21.66 cm(cid:0) 1 band around 2916 could be due to the C-H stretching vibration 0.577 ± that might have been derived from the organic molecules of the extract.”
Green synthesis and characterization of titanium dioxide nanoparticles using leaf extract of Pouteria campechiana and larvicidal and pupicidal activity on Aedes aegypti DOI: 10.1016/j.envres.2021.111333 -
Alkyl C-H confidence 1.0
“OH group around at 3444 stretching of symmetric C-H at 2916 cm-1 and cm-1.”
Nanostructure and Property of Electrospun SiO2-Cellulose Acetate Nanofiber Composite by Electrospinning DOI: 10.1016/j.egypro.2016.12.133 -
Alkyl C-H confidence 1.0
“7a) shows characteristic 2848cm(cid:1)1 absorption peaks at 2916 and which are ascribed to CAH stretching vibration of long alkyl chain.”
Olajire 和 Mohammed - 2020 - Green synthesis of nickel oxide nanoparticles and DOI: 10.1016/j.apt.2019.10.012 -
Alkyl C-H confidence 1.0
“Several SA-LB films symmetric and asymmetric C-H stretching mode of the CH 2 were prepared on SCG substrate with a different number of 2916cm-1 groups at 2849 and and to asymmetric stretching deposited monolayers: They were constituted of o”
Peruchon 等 - 2008 - Characterization of self-cleaning glasses using La DOI: 10.1016/j.jphotochem.2007.12.033 -
Alkyl C-H confidence 1.0
“mined cm-1 cm-1 3600-3200 while a less intense peak at 2916 correFrom Table 1, it is clear that best grafting percentage was obtained to C H stretching vibrations of CH group has been reported spond exposure time was 4 min.”
Shahid 等 - 2013 - Graft polymerization of guar gum with acryl amide DOI: 10.1016/j.ijbiomac.2013.08.018 -
Alkene (C=C) confidence 1.0
“2, the of nonsaturated double bond absorb peak cm(cid:2)1 absorption peak intensity of 2916 area with plasma discharge time is reverse to that methylene”
Shi 等 - 2006 - The investigation of argon plasma surface modifica DOI: 10.1016/j.eurpolymj.2006.01.007 -
Acetate confidence 1.0
“CH 2, and C-O groups was also characterized at peaks of cm-1 2916, 2847, and 2854 [20, 32, 45, 59, 62].”
Nanostructural, Chemical, and Thermal Changes of Oil Palm Empty Fruit Bunch Cellulose Nanofibers Pretreated with Different Solvent Extractions DOI: 10.1007/s12649-017-0098-4 -
Hydroxyl (O-H) confidence 1.0
“cm-1 of 4000-400 The band at around 2916 correspond to the stretching vibration of the cm-1 hydroxyl ion [45].”
Abozaid 等 - 2018 - Characterization of Neodymium Doped Calcium Tungst DOI: 10.2298/SOS1804445A
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