What absorbs at 2914 cm⁻¹ in an FTIR spectrum?
A band near 2914 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 2914 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 | 30 | 29 | 1.0 |
| Methyl | 5 | 5 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Lipid | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Fatty acid | 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 | 2914, 1660, 2930 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 1 |
| PVC | 2914, 834, 1195 | Alkyl C-H, Methoxy (OCH3), Methacrylate | 1 |
| polysaccharide | 2914, 1637, 1320 | Methacrylate, Alkyl C-H, Methoxy (OCH3) | 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 2914 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
“LLM confirmed rule peak-group candidate”
Understanding Hydrothermal Dechlorination of PVC by Focusing on the Operating Conditions and Hydrochar Characteristics DOI: 10.3390/app7030256 -
Alkyl C-H confidence 1.0
“2924 X (2926) X X (2929) X (2922) X (2927) X (2927) cm-1 2924 assigned to symmetric and asymmetric stretching of -C-H 2914 X (2910) X X”
Getting inside on virgin olive oil (VOO) photooxidation kinetics through combined generalized 2D correlation analysis and moving window 2D correlation analysis of ATR-FTIR spectra DOI: 10.1016/j.talanta.2020.120917 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
CMC stabilized nano silver synthesis, characterization and its antibacterial and synergistic effect with broad spectrum antibiotics DOI: 10.1016/j.carbpol.2016.11.083 -
Alkyl C-H confidence 1.0
“The peak at 2914 cm-1 corresponds to the methylene C-H asymmetrical stretching.”
Walnut Oil Oleogels as Milk Fat Replacing System for Commercially Available Chocolate Butter DOI: 10.3390/gels8100613 -
Alkyl C-H confidence 1.0
“The Peak at 2914 is indication of C-H stretch;”
Extraction purification and characterization of galactomannan from fenugreek for industrial utilization DOI: 10.1016/j.carbpol.2017.10.025 -
Alkyl C-H confidence 1.0
“cm-1 are due to the C-Cl observed between 600 and 700 trum of the GO coated with APTES (fGO) gives charactercm-1 cm-1 stretching vibrations, the band at 1435 is assigned to istic absorption peaks at 1036 for Si-O-C bond and cm-1 cm-1 the CH”
Dynamic mechanical and optical characterization of PVC/fGO polymer nanocomposites DOI: 10.1007/s00339-018-2026-2 -
Alkyl C-H confidence 1.0
“4 shows two sharp bands at 2914 and 2890 that can be attributed to the stretching vibration of C-H of aliphatic methyl and/or methylene groups, which A is in line with the spectra previously reported for microcrystalline wax (Hassan et al,”
Yudha 等 - 2019 - A SEM study of unexplored wax microtubes produced DOI: 10.1016/j.micron.2019.102729 -
Alkyl C-H confidence 1.0
“2938.75 C-H stretching vibration of 2920.14 the CH,CH and CH stretch form alkyl 2914.06 2 3 groups (2800-3000)cm-1 C=O carbonyl stretch”
Abead 等 - 2023 - Study physical characteristics of Polyvinyl Alcoho DOI: 10.15764/pche.2014.02001.
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