What absorbs at 1565 cm⁻¹ in an FTIR spectrum?
A band near 1565 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 1565 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 |
|---|---|---|---|
| Amide | 10 | 10 | 1.0 |
| Carboxyl (COOH) | 5 | 5 | 1.0 |
| Ring structure | 5 | 5 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Secondary amine | 4 | 4 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Aromatic ring | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Carbonyl (C=O) | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| Ketone | 3 | 3 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| C=n | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Quinone | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.95 |
| Acetyl | 1 | 0 | 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 |
|---|---|---|---|
| polyaniline | 1565, 1570, 1300 | Amide, Ring structure | 3 |
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 1565 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
-
Hydrogen bond confidence 1.0
“11(a) betweenpolymerandpolymerandthepeakobservedat1565cm(cid:1)1 and(b), and Table 8 shows the vibrational spectra (for stretching to the hydrogen bonds between polymer and water.”
Atomic scale characterization of the conformational dynamics of a thermo-sensitive and a non-thermo-sensitive oligomer using vibrational spectra obtained from molecular dynamics DOI: 10.1016/j.polymer.2012.01.022 -
C c single bond confidence 1.0
“Raman band at 1615 cm-1 cm-1 is attributed to C-C stretching vibration of benzene ring, and Raman band at 1565 is”
Jin 等 - 2018 - Polymer anode used in hydrometallurgy Anodic beha DOI: 10.1016/j.hydromet.2018.01.020 -
Amide confidence 1.0
“only, and the peak shifts a little to 1565 Figure 12b shows the peak shift vs strain curve of the amide R II vibration for the films.”
Loo 和 Gleason - 2003 - Insights into structure and mechanical behavior of DOI: 10.1021/ma034213v -
Ring structure confidence 1.0
“The 1565 band (A2) contains the ring vibrations of both the imidazole and C4=C5, pyrimidine rings.”
Peng 等 - 2011 - Anharmonic Vibrational Modes of Nucleic Acid Bases DOI: 10.1021/ja205636h -
Nitrogen heterocycle confidence 1.0
“cm-1 is caused by the The absorption peak at 1565 resin distributed more uniformly, with the particle size stretching vibration of the C = N of the triazine ring in distributed mainly between 1 and 10 nm.”
Qin 等 - 2023 - Preparation and properties of silica solmelamine DOI: 10.1080/15685551.2022.2162280 -
Aromatic ring confidence 1.0
“The change in degree of oxidation may also lead main peaks consistent with quinone and benzene ring deforma1564.7cm-1 1464.0cm-1 to change in electrical conductivity of polyaniline which again tions are observed at and [15,36].”
Raigaonkar 等 - 2011 - Structural and spectral investigations of anthrace DOI: 10.1016/j.synthmet.2010.12.002 -
confidence 1.0
“In the spectrum of Am-rGO, the N-H deformation peaks at 1565 cm-1;”
Preparation of Electrospun Nanocomposite Nanofibers of Polyaniline/Poly(methyl methacrylate) with Amino-Functionalized Graphene DOI: 10.3390/polym9090453 -
Carboxyl (COOH) confidence 1.0
“Analysis of unmounted fragments of the sample cm-1, the zinc carboxylate bands between 1565 and 1516 determined that the protrusion (1) is composed primarily of zinc soaps with small quantities of free fatty acids and is shown in Fig.”
Henderson 等 - 2019 - Infrared chemical mapping of degradation products DOI: 10.1186/s40494-019-0313-7
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