What absorbs at 2912 cm⁻¹ in an FTIR spectrum?
A band near 2912 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 2912 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 | 19 | 19 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| N h | 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 |
| Aromatic ring | 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 |
|---|---|---|---|
| PVA | 2912, 1660, 2930 | Alkyl C-H, Hydroxyl (O-H), Methoxy (OCH3) | 1 |
| chitosan | 2912, 1650, 1655 | Alkyl C-H, Hydroxyl (O-H), N h | 1 |
| ZnO | 2912, 1400, 3430 | Hydroxyl (O-H), Alkyl C-H, Methoxy (OCH3) | 1 |
| ZnS | 2912, 1650, 1116 | Hydroxyl (O-H), Alkyl C-H | 1 |
| PVC | 2912, 834, 1195 | Alkyl C-H, Methoxy (OCH3), Hydroxyl (O-H) | 1 |
| cellulose nanocrystals | 2912, 1110, 1640 | Methoxy (OCH3), 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 2912 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
-
Hydroxyl (O-H) confidence 1.0
“Thus, based on the spectra for CALcm-1 For the FTIR spectra of pure 2,4-DP, the peak at 2912 2,4DP, the nanocomposite resembles the absorption is associated with the stretching vibration of the O-H bands in both LDH and 2,4-DP.”
Bohari 等 - 2022 - Synthesis and Characterization of 2,4-Dichlorophen DOI: 10.22146/ijc.73546 -
Alkyl C-H confidence 1.0
“Meanwhile, the red amaranth extract showed several organic functional groups from chlorophyll and betalain compounds, such as O-H and N-H cm-1), sp3 cm-1), cm-1), stretching (3670-2985 C-H stretching (2912 C=O is stretching (1630 C=C and C=”
Kurniawan 等 - 2019 - Selective Betalain Impregnation from Red Amaranth DOI: 10.1063/1.5134613 -
Alkyl C-H confidence 1.0
“Whereas, all of the spectra exhibited around 2912 cm-1 indicated the characteristics of C-H stretching vibrations consist in cellulose components, interrelating to the lignin molecules [15].”
Extraction and Characterization of Cellulose Nanocrystals from Tea Leaf Waste Fibers DOI: 10.3390/polym9110588 -
Alkyl C-H confidence 1.0
“The absorption peaks at 2912, 2874 are attributed to the asymmetric stretching of (C-H bond;”
Bio-Based (Chitosan-ZnO) Nanocomposite: Synthesis, Characterization, and Its Use as Recyclable, Ecofriendly Biocatalyst for Synthesis of Thiazoles Tethered Azo Groups DOI: 10.3390/polym14030386 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Weathering Characteristics of Wood Plastic Composites Reinforced with Extracted or Delignified Wood Flour DOI: 10.3390/ma9080610 -
Alkyl C-H confidence 1.0
“~2912 For all NCSPEs, the IR band due to C-H stretch diminished except for ZN10.”
Substantial Proton Ion Conduction in Methylcellulose/Pectin/Ammonium Chloride Based Solid Nanocomposite Polymer Electrolytes: Effect of ZnO Nanofiller DOI: 10.3390/membranes12070706 -
Alkyl C-H confidence 1.0
“The PVC polymer's cm-1, cm-1, CH stretching, CH bending, and CH rocking vibrations are located at 2912 1429 cm-1, and 1130 respectively [33,34].”
Impact of ZnS/Mn on the Structure, Optical, and Electric Properties of PVC Polymer DOI: 10.3390/polym15092091 -
Hydroxyl (O-H) confidence 1.0
“The peaks at around 2912 are assigned to cm-1 at 3345 also corresponds to hydroxyl groups.”
Fahma 等 - 2017 - PVA nanocomposites reinforced with cellulose nanof DOI: 10.9755/ejfa.2016-02-215
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