What absorbs at 3050 cm⁻¹ in an FTIR spectrum?
A band near 3050 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 3050 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 | 18 | 15 | 1.0 |
| Aromatic ring | 10 | 5 | 1.0 |
| Hydroxyl (O-H) | 7 | 5 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Methyl | 3 | 3 | 1.0 |
| Oxygen heterocycle | 3 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 0.8 |
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 | 3050, 1660, 2930 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| PLGA | 3050, 3200, 1741 | 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 3050 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
“Peak B at 3050 cm-1 are due to the methyl stretches.”
Chan 和 Bogomolni - 2012 - Structural Water Cluster As a Possible Proton Acce DOI: 10.1021/jp304934t -
Aromatic ring confidence 1.0
“Aromatic hydrogen stretching at 3050 The spectra of the standard PAH used for the aromatic hydropeak is clearly observed in n-propyl-benzene and isopropyl-”
Infrared spectroscopy of some carbon-based materials relevant in combustion: Qualitative and quantitative analysis of hydrogen DOI: 10.1016/j.carbon.2014.03.014 -
Oxygen heterocycle confidence 1.0
“characteristic signals of the terminal groups of both precursors (3-GPTMS-epoxy ring, cm-1) Jeffamine THF 170-NH terminal group, 1578 [39] are not present, showing that the 3050 cm-1 [41];”
Hybrid Sol–Gel Matrices Doped with Colorimetric/Fluorimetric Imidazole Derivatives "2279 DOI: 10.3390/nano11123401 -
Acetate confidence 1.0
“In agreement with what observed between 3050 and 2800 and 2800 cm-1, the CH2/CH3 band at ~1468 cm-1 was found to slightly increase in intensity cm-1 the CH 2/CH band at ~1468 was found to slightly increase in intensity in ATX3-Q55 3 in ATX3”
Pathological ATX3 Expression Induces Cell Perturbations in E. coli as Revealed by Biochemical and Biophysical Investigations DOI: 10.3390/ijms22020943 -
Aromatic ring confidence 1.0
“LLM confirmed rule peak-group candidate”
Synthesis of polyimides from α,αʹ-bis(3-aminophenoxy)-p-xylene: Spectroscopic, single crystal XRD and thermal studies DOI: 10.1016/j.molstruc.2018.01.098 -
Alkyl C-H confidence 1.0
“3400 -O-H Stretching Vibration w 3050 -C-H Stretching Vibration 1610”
Bargujar 等 - 2022 - A new polysaccharide-based ion-exchange resin for DOI: 10.14314/polimery.2022.5.4 -
Alkyl C-H confidence 1.0
“In addition, in this phase of growth a weak intensity cm-1 reduction of the CH bands between 3050 and 2800”
Protein aggregation and membrane lipid modifications under lactic acid stress in wild type and OPI1 deleted Saccharomyces cerevisiae strains DOI: 10.1186/s12934-016-0438-2 -
Alkyl C-H confidence 1.0
“of-OH chain.28 Thequite narrow spectra groupisindicativeof thefact ment of monomers and carbon The infra-red spectra cm(cid:1)1 ciprofloxacin that water is not adsorbed on the surface of nanoparticles, and of pure show the band at 3050 due”
Poly Lactic-Co-Glycolic Acid Nano-Carriers for Encapsulation and Controlled Release of Hydrophobic Drug to Enhance the Bioavailability and Antimicrobial Properties DOI: 10.1177/15593258231152117
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