What absorbs at 1516 cm⁻¹ in an FTIR spectrum?
A band near 1516 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 1516 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 | 8 | 7 | 1.0 |
| Aromatic ring | 5 | 5 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Amino acid | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Sulfur heterocycle | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 0.8 |
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 | 1516, 1565, 1570 | Aromatic ring, Amide, Ring structure | 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 1516 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
-
Acetate confidence 1.0
“Lignin 1637.56 1653.00 1658.78 [6] (unconjugated) C=O stretching Lignin 1516.05 1514.12 1514.12 [6]”
Firsoni 等 - 2019 - Fiber Content and Relative Feed Value Estimation o DOI: 10.1088/1757-899X/546/4/042008 -
C c single bond confidence 1.0
“C_C ring stretching at 1516 The FT-IR spectrums of ferulic 3.4.Apparentviscosity acid-graftedwater-solublecurdlanconjugatesalsoappearednewchar-”
Catechin-grafted arabinoxylan conjugate: Preparation, structural characterization and property investigation DOI: 10.1016/j.ijbiomac.2021.03.190 -
Aromatic ring confidence 1.0
“The presence of a positive-going band at 1516 reveals CAC the vanishing of aromatic vibrations at 1.0 V in PANI (the referencespectrumwasacquiredpreviouslyat0.1V).Theactivationofthis vibrational mode under s-polarized radiation is associate”
Revisiting the Redox Transitions of Polyaniline. Semiquantitative Interpretation of Electrochemically Induced IR Bands DOI: 10.1016/j.jelechem.2021.115593 -
Lignin confidence 1.0
“In regard to the peak at 1516 cm-1, which has been previously assigned to lignin according to Lahlali et al.”
Specific Mycoparasite-Fusarium Graminearum Molecular Signatures in Germinating Seeds Disabled Fusarium Head Blight Pathogen’s Infection DOI: 10.3390/ijms22052461 -
Carbohydrate confidence 1.0
“Therefore, selection based on other related (1737.8, 1267.2, and 969.2 proteins (1688.6 and cm-1), characters such as FHB severity or percent scabby seed 1544.9 cellulose vibrations (1516, 1463.9, 1374.2, cm-1), has been proposed [7,59].”
Synchrotron based phase contrast X-ray imaging combined with FTIR spectroscopy reveals structural and biomolecular differences in spikelets play a significant role in resistance to Fusarium in wheat DOI: 10.1186/s12870-014-0357-5 -
Ring structure confidence 1.0
“1708 peak became far less prominent in the D 2O A strong produces a sharp peak/trough at 1533/1522 cm-1 sample, consistent with a shift downward by around 4 ring-bending mode of free tyrosine occurs in water at 1516 cm-1 and/or a decrease o”
Rich 和 Breton - 2001 - FTIR studies of the CO and cyanide adducts of full DOI: 10.1021/bi0027332 -
Amino acid confidence 1.0
“cm-1, cm-1 cm-1), 1634-1635 1594-1598 1652 and amide II cm-1), cm-1), (1547-1548 peaks the tyrosine peak (1516 the Karolinska”
Shi 等 - 2018 - Biochemical alterations of Candida albicans during DOI: 10.1039/c8an01452c -
Hydroxyl (O-H) confidence 1.0
“modern and sub-fossil spectra, (iv) indicates the UAC peak region at 1516 and (v) the O-H peaks around 3,300 cm-1, the hydroxyl OH peak at ~3,300 and we also observe increases Similarly, there was a relatively small distance between KOH-tre”
Influence of common palynological extraction treatments on ultraviolet absorbing compounds (UACs) in sub-fossil pollen and spores observed in FTIR spectra DOI: 10.3389/fevo.2023.1096099
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