What absorbs at 1504 cm⁻¹ in an FTIR spectrum?
A band near 1504 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 1504 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 |
|---|---|---|---|
| Aromatic ring | 10 | 10 | 1.0 |
| Alkene (C=C) | 8 | 8 | 1.0 |
| Lignin | 7 | 6 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbohydrate | 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 | 1504, 1660, 2930 | Amide | 1 |
| PE | 1504, 1414, 1700 | Aromatic ring | 1 |
| PP | 1504, 1700, 1043 | Aromatic ring | 1 |
| wood | 1504, 1740, 1730 | Lignin, Aromatic ring | 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 1504 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
-
Carbohydrate confidence 1.0
“that both the samples have cellulose I crystalline properties out cm-1 this region comprised of peaks at 1504 whereas for B and also posses with high amorphous content.”
Das 等 - 2017 - Extraction of xylem fibers from Musa sapientum and DOI: 10.1007/s12221-017-1187-5 -
Aromatic ring confidence 1.0
“The cm-1 band at 1504 is attributed to the phenyl nucleus”
Surender 等 - 2014 - Bismaleimide and Bispropargyl Ether Blends Curing DOI: 10.1134/S1560090414050157 -
Alkene (C=C) confidence 1.0
“The 2 cm-1, cm-1, cm-1 C=C stretching vibrations at 1594 cm-1, 1504 cm-1, and 1460 cm-1 of lignin and -CHskeletal C=C stretching vibrations at 1594 1504 and 1460 of lignin and cm-1 stretching vibrations at 1425 cm-1 are all present in raw-K”
Blaquera 等 - 2023 - Oil Adsorption Kinetics of Calcium Stearate-Coated DOI: 10.3390/polym15020452 -
Aromatic ring confidence 1.0
“A unique spectral feature of PC was a band at 1504 assigned to an aromatic ring vibration.”
Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification DOI: 10.1038/s41598-022-23318-2 -
Carbonyl (C=O) confidence 1.0
“The dispersion (EDXRF) cm-1 peak at 1504 is attributed to the carbonyl functional”
Boscariol 等 - 2022 - Characterization of Commercially Available Turmeri DOI: 10.21577/0103-5053.20220073 -
Alkene (C=C) confidence 1.0
“cm-1 particular, the two bands located at 1504 and 811 can be ascribed to the ν(C=C) stretching of the conjugated aromatic system respectively.53 These bands and to the τ(C-H) out of plane bending”
Dani 等 - 2017 - Click-based porous cationic polymers for enhanced DOI: 10.1039/x0xx00000x -
Lignin confidence 1.0
“Then, the average value cm-1 cm-1 for the lignin peak between 1504 and 1513 was determined, which is considered for the lignin peak between 1504 cm-1 and 1513 cm-1 was determined, which is considered cm-1.”
Analysis of the Natural Aging of Silver Fir (Abies alba Mill.) Structural Timber Using Dendrochronological, Colorimetric, Microscopic and FTIR Techniques DOI: 10.3390/f14071363 -
Metal oxygen confidence 1.0
“For due to interactions with anatase TiO 2 example,thebandsat1585cm-1,1504cm-1,and1288cm-1, and nanocomposites were performed by using an Iviumstat C=N, C=C, electrochemical working station (Ivium Technologies BV).”
Guo 等 - 2012 - Preparation of a Novel Nanocomposite of Polyanilin DOI: 10.1155/2012/202794
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