What absorbs at 1586 cm⁻¹ in an FTIR spectrum?
A band near 1586 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 1586 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 | 7 | 7 | 1.0 |
| Alkene (C=C) | 5 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Ring structure | 2 | 1 | 1.0 |
| Alkyl C-H | 2 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Lignin | 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 |
|---|---|---|---|
| nanotubes | 1586, 1735, 1630 | Carboxyl (COOH), Alkene (C=C) | 1 |
| lignin | 1586, 1035, 1510 | Aromatic ring | 1 |
| wood | 1586, 1740, 1730 | Aromatic ring | 1 |
| PET | 1586, 1408, 800 | Amide | 1 |
| silver nanoparticles | 1586, 1636, 1631 | Amide | 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 1586 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
-
Carboxyl (COOH) confidence 1.0
“however, the additional peaks for C cm1 1586 likely corresponds to the carboxyl group's ν(- and O indicate that the nanoparticles are mixed into”
Manullang 等 - 2021 - Plant-extract-mediated biosynthesis of silver nano DOI: 10.13057/nusbiosci/n130216 -
Aromatic ring confidence 1.0
“The characteristic peaks at 1586 1375 and 1171 refers to cm-1 tri-phenyl-methane dyes and the prominent peak at 1586 has clearly indicated the C= C cm-1 stretching of the benzene ring.”
Trichoderma asperellum laccase mediated crystal violet degradation–Optimization of experimental conditions and characterization DOI: 10.1016/j.jece.2016.11.044 -
Alkene (C=C) confidence 1.0
“LLM confirmed rule peak-group candidate”
Babar 和 Sarkar - 2017 - Self-assembled nanotubes from single fluorescent a DOI: 10.1007/s13204-017-0551-5 -
confidence 1.0
“deformations of the amine bound to the metal-0.933 for 1589/1581cm-1 1586cm-1 A red shift of the amine scissoring modes, occurring at (Raman), 1588/1573cm-1 (FTIR) and (INS), was detected relative to the free diaminopropane ligand and simil”
Batista de Carvalho 等 - 2012 - Pt(II) Complexes with Linear Diamines-Part I Vibr DOI: 10.1155/2012/206297 -
Lignin confidence 1.0
“wood disappeared and instead appeared as two bands, 1586 and 1531 The first corresponds to the lignin from wood and the second to the carboxylate group (-COO-), [32] or C=C from rubber.”
The Influence of Fly Ash on the Mechanical Properties of Water Immersed All Waste Composites DOI: 10.3390/polym14101957 -
Alkene (C=C) confidence 1.0
“An increase in the absorption band located at 1586 indicates an increase in C=C polymer matrix.”
Purification and Glutaraldehyde Activation Study on HCl-Doped PVA–PANI Copolymers with Different Aniline Concentrations DOI: 10.3390/molecules24010063 -
Amide confidence 1.0
“Both prostate and 1556 proteins) in the amide I and amide II cm-1 1750-1700 (CvO CSCs and non-CSCs have positive peaks in the lipid region regions, between groups), at 1586, 1570 cm-1), cm-1 (COO- (3000-2800 while they have negative values”
Guler 等 - 2019 - Characterization of CD133(+)CD44(+) human prostat DOI: 10.1039/c9an00093c -
Amide confidence 1.0
“North East England: EDB) indicating that Japanese knotweed from within each knotweeds collected in the WS, in particular at around 1 1 region share common properties that are distinct from 1648 cm- (Amide I band), 1586 cm- (Amide II band)”
Regional differences in clonal Japanese knotweed revealed by chemometrics-linked attenuated Total reflection Fourier-transform infrared spectroscopy DOI: 10.1186/s12870-021-03293-y
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