What absorbs at 1509 cm⁻¹ in an FTIR spectrum?
A band near 1509 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 1509 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 | 13 | 12 | 1.0 |
| Alkene (C=C) | 8 | 8 | 1.0 |
| Lignin | 5 | 5 | 1.0 |
| Ring structure | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 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 |
| Carbohydrate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Methyl | 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 |
|---|---|---|---|
| epoxy resin | 1509, 905, 1100 | 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 1509 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
-
Alkene (C=C) confidence 1.0
“In both cases the characteristic absorption bands are showed: 1509 and 1608 cm-1 (C=C bonds of aromatic ring), 1457 cm-1 (CH2 group vibration), 1362 cm-1 (methyl group vibration) and”
Barbadillo 等 - 2003 - Study of a curing reaction of an epoxy resin DOI: 10.4028/www.scientific.net/MSF.426-432.2163 -
Amino acid confidence 1.0
“cm-1 ν(CN), δ(CH), δ(NH), of stretching vibrations, of the amino acid tryptophan, that is found at 1509 cm-1) P.”
Gupta 等 - 2022 - In vitro cell composition identification of wood d DOI: 10.1098/rsos.201935 -
confidence 1.0
“The peak of N-H, attributed to the deformation of urethane dimethacrylate at 1509 cm-1, also showed a low intensity (EC-C~0.14, EC-Z1~0.05, and EC-Z2~0.04).”
Structural, Physical, and Mechanical Analysis of ZnO and TiO2 Nanoparticle-Reinforced Self-Adhesive Coating Restorative Material DOI: 10.3390/ma14247507 -
Aromatic ring confidence 1.0
“C]C e e e e aromatic ring (stretching) 1485 1485 1490 1494 1494 1494 s C]C e e e e aromatic ring (stretching) 1509 1512 1508 1599 1599 1599 s”
Hydrogen separation performance of CMS membranes derived from the imide-functional group of two similar types of precursors DOI: 10.1016/j.ijhydene.2011.03.146 -
Carbonyl (C=O) confidence 1.0
“The peaks at 1509 in as prepared composite powders are due to cm-1 asymmetric stretching vibration of carbonyl group.”
Structural, optical, morphological and thermal properties of TiO2–Al and TiO2–Al2O3 composite powders by ball milling DOI: 10.1016/j.physleta.2017.02.053 -
N n bond confidence 1.0
“This cm-1) was confirmed by the removal of signature peaks of aromatic C-H bending (645, 759 and 831 and the N=N peak cm-1 at 1509 of the FTIR spectrum of the metabolites.”
Influence of redox mediators and media on methyl red decolorization and its biodegradation by Providencia rettgeri DOI: 10.1007/s42452-019-0668-0 -
Aromatic ring confidence 1.0
“cm¡1 -N-H 2800 showed stretching vibrations in and C-H Gas sensing analysis respectively.[29-31] bonds, Poly (N-ethyl aniline) gave an cm¡1 The study showed that poly (N-ethyl aniline)/iron and absorption band at 1509 corresponding to the a”
Synthesis, characterization, and application of poly \(N-ethyl aniline\)/iron nanocomposite DOI: 10.1080/15533174.2016.1186083 -
Aromatic ring confidence 1.0
“The peaks at 1509, 1423, 1265 and 1023 represent C=C 5 ACCEPTED MANUSCRIPT stretching of aromatic rings, methoxy (O-CH 3) and symmetric C=O stretching and C-O-C bond [20].”
Enhanced arsenic (iii) adsorption from aqueous solution by magnetic pine cone biomass DOI: 10.1016/j.matchemphys.2018.09.067
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