What absorbs at 1566 cm⁻¹ in an FTIR spectrum?
A band near 1566 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 1566 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 | 11 | 10 | 1.0 |
| Secondary amine | 5 | 4 | 1.0 |
| C n single bond | 5 | 4 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Aromatic ring | 3 | 3 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Alkene (C=C) | 2 | 1 | 1.0 |
| N-O bond | 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 |
| Methyl | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Boron nitrogen | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Hydrogen bond | 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 | 1566, 1565, 1570 | Amide, Secondary amine, C n single bond | 2 |
| cellulose | 1566, 1735, 1650 | Amide | 1 |
| hemicellulose | 1566, 1730, 897 | Amide | 1 |
| GO | 1566, 1720, 1182 | Amide | 1 |
| rGO | 1566, 2358, 2930 | Amide, N h | 1 |
| PCL | 1566, 1751, 1724 | 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 1566 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
-
N h confidence 1.0
“1566cm-1, R2 due to NH in-plane bending, triazine stretching In every case a, good linear fit was obtained with valand C-N stretching, respectively, [23] and so, these bands ues >0.999.”
Armenta 等 - 2004 - Determination of cyromazine in pesticide commercia DOI: 10.1016/j.aca.2004.02.063 -
Ring structure confidence 1.0
“is corresponds to stretching ing, 1566 cm(cid:1)1 C¼¼N Figure 2(a) shows that SEM image of pure Polyquinoid ring, 1548 for bond stretching, cm(cid:1)1 aniline highly agglomerated granular in shape and is corresponds to stretching vibration”
Studies on Fourier transform infrared spectroscopy, scanning electron microscope, and direct current conductivity of polyaniline doped zinc ferrite DOI: 10.1002/app.33600 -
Aromatic ring confidence 1.0
“The characteristic absorption peaksarefoundtobeat2922cm-1isduetotheC Hstretching,1566cm-1iscorrespondsto cm-1 cm-1 C stretching vibration of quinoid ring, 1548 for C N bond stretching, 1494 C cm-1 is corresponds to stretching vibration of b”
Patil 等 - 2011 - Electrical Conductivity of PolyanilineNiZnO3 Comp DOI: 10.1080/00150193.2011.620836 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Aamir 和 Ahmad - 2010 - Production and Stability Evaluation of Modified-Re DOI: 10.1208/s12249-010-9392-1 -
Aromatic ring confidence 1.0
“LLM confirmed rule peak-group candidate”
A novel multicopper oxidase (laccase) from cyanobacteria: Purification, characterization with potential in the decolorization of anthraquinonic dye DOI: 10.1371/journal. -
Amide confidence 1.0
“The resting (control) macrophages cm-1 The number of bacteria recovered from demonstrated FTIR spectra at 3412 (O-H cm-1 the host-pathogen interface assay (Table 1) stretch), 1698 (C=O acidic stretch), 1566 cm-1 demonstrated significantly (”
El Mohtadi 等 - 2020 - DIFFERENTIAL ENGULFMENT OF STAPHYLOCOCCUS AUREUS A DOI: 10.17179/excli2020-2766 -
Silicon (Si) confidence 1.0
“The missing - Dbc Si stretch 1566 (1607.3*) 0.94 Habenergy is provided by one (or more) bulk phonon(s).”
Gibbons 等 - 2013 - Huge isotope effect on the vibrational lifetimes o DOI: 10.1103/PhysRevB.87.115207 -
confidence 1.0
“The absorption peak of C=O in amide-I changed to 1638 cm-1, whereas the absorption peak of N-H in amide-II shifted to 1566 cm-1, suggesting that the amide carbonyl (C=O) and N-H of the amide bond contributed Foods 2022, 11, x FOR PEER REVIE”
Purification and Characterization of a Novel Calcium-Binding Heptapeptide from the Hydrolysate of Tilapia Bone with Its Osteogenic Activity DOI: 10.3390/foods11030468
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