What absorbs at 3051 cm⁻¹ in an FTIR spectrum?
A band near 3051 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 4 cited sources
Quick answer
A band near 3051 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 | 4 | 4 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
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 3051 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
-
C c single bond confidence 1.0
“The characteristic bands of naphthyl are T3 result is consistent with the expected chemical shift of the silsesquioxane linked to a also observed, with the C-C and C-H stretching modes observed at 1600 and 3051 cm-1,”
Thiolated Janus Silsesquioxane Tetrapod: New Precursors for Functional Materials DOI: 10.3390/molecules27227680 -
Alkyl C-H confidence 1.0
“:3 0 :3 8 120-122 67 170 81 68 The characteristics vibration of dibenzalpropanone in FTIR was identified at 3228.84 (C-H aliphatic sp2 cm-1 stretching), 3051.39 and 3028.24 (aromatic C-H stretching), 1651.07 (C=O stretching), 1593.20 (aroma”
Mardiana 等 - 2017 - Ultrasound-Assisted Synthesis of Curcumin Analogs DOI: 10.1063/1.4991200 -
confidence 1.0
“IR spectrum, max,- 4:26:12 2 cm(cid:4)1: 7.48-7.51 ¼ C-H m, Ar-H), (2H, m, Ar-H), 7.60 (1H, t, J 7.2 Hz, Ar-H), 3490 & 3379 (amine stretching), 3051 (aromatic ¼”
Coumarin–carbazole based functionalized pyrazolines: synthesis, characterization, anticancer investigation and molecular docking DOI: 10.1039/d1ra03970a -
Acetate confidence 1.0
“Rheological Behavior and Density Characteristic bands were identified in the spectrum of the pure lactic acid in the Viscosity data are relevant for the design stage of industrial processes, fluid flow region between 2834 cm-1 and 3051 cm-1”
Elaboration and Characterization of Natural Deep Eutectic Solvents (NADESs): Application in the Extraction of Phenolic Compounds from pitaya DOI: 10.3390/molecules27238310
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