What absorbs at 1546 cm⁻¹ in an FTIR spectrum?
A band near 1546 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 1546 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 | 19 | 16 | 1.0 |
| N h | 5 | 4 | 1.0 |
| Protein | 3 | 3 | 1.0 |
| Aromatic ring | 3 | 2 | 1.0 |
| Alkyl C-H | 3 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Ring structure | 2 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Anhydride | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
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 1546 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
-
Amide confidence 1.0
“bending of protein The band at 1546 is assigned to amide II for N-H in-plane bending”
Gupta 等 - 2022 - In vitro cell composition identification of wood d DOI: 10.1098/rsos.201935 -
Ring structure confidence 1.0
“9a) The peak at 1546 is related to -C=Cstretching in 2-5 di-substituted furanic ring [21].”
Singh 等 - 2022 - Degradation of Polyfurfuryl Alcohol-Based Biopolym DOI: 10.21203/rs.3.rs-546187/v1 -
Amide confidence 1.0
“45, 2006 13457 bicarbonate, respectively, ligated to the non-heme iron (55), cm-1 Fe3+/ and the peak near 1546 [at 1552 in the original Fe2+ spectrum (55, 56)] is probably due to the amide II band.”
Suzuki 等 - 2006 - Structural perturbation of the carboxylate ligands DOI: 10.1021/bi061232z -
confidence 1.0
“7c, revealed amide I and amide II peaks at 1641 (C = O stretching, cm1 CONH) and 1546 (N-H bending), respectively.”
Azrak 等 - 2021 - Controlled Dispersion and Setting of Cellulose Nan DOI: 10.21203/rs.3.rs-376512/v1 -
confidence 1.0
“intense bands at 1449 and 1611 For SiBEA a very low amount of Brønsted and Lewis acidic centers was proven cm-1 (Table 5) by the appearance of low bands at 1546 and 1638 typical for pyridine cations, cm-1, and at 1455 attributed to coordina”
Baran 等 - 2016 - Influence of the nature and environment of cobalt DOI: 10.1016/j.micromeso.2015.12.061 -
Protein confidence 1.0
“the peak 1546 is associated with bending and stretching vibrations, whereby the protein;”
Cavalcante 等 - 2020 - Chlorapatite Derived from Fish Scales DOI: 10.3390/ma13051129 -
Protein confidence 1.0
“1652cm-1 1546cm-1 and were assigned to protein amide C”
Dogan 等 - 2020 - Dose-Dependent Differentiation of Gamma-Irradiated DOI: 10.1155/2020/8859104 -
Silicon (Si) confidence 1.0
“ing and CNH) bands correspond to 1651 and 1546 cm-1 was attributed to the Si-CH band, and 800 was attributed to the CH 2-Si-O vibrations.”
Effects of Hybrid Polymeric Material Based on Polycaprolactone on the Environment DOI: 10.3390/ma15144868
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