What absorbs at 1535 cm⁻¹ in an FTIR spectrum?
A band near 1535 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 1535 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 | 34 | 32 | 1.0 |
| N h | 16 | 15 | 1.0 |
| Carboxyl (COOH) | 7 | 7 | 1.0 |
| Alkyl C-H | 7 | 7 | 1.0 |
| Secondary amine | 6 | 6 | 1.0 |
| C n single bond | 6 | 6 | 1.0 |
| Alkene (C=C) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Aromatic ring | 3 | 3 | 1.0 |
| Carbonyl (C=O) | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Nitro (NO2) | 1 | 0 | 1.0 |
| Ring structure | 1 | 0 | 1.0 |
| Bronsted acid site | 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 |
|---|---|---|---|
| nanotube | 1535, 1540, 1080 | Amide, N h, Alkyl C-H | 1 |
| TiO2 | 1535, 1700, 1093 | Alkyl C-H, Carboxyl (COOH) | 1 |
| polyvinylpyrrolidone | 1535, 1660, 1700 | Amide, Alkyl C-H, Carboxyl (COOH) | 1 |
| polyaniline | 1535, 1565, 1570 | Amide, Alkyl C-H | 1 |
| copolymer | 1535, 2921, 1540 | Alkyl C-H, Amide, Carboxyl (COOH) | 1 |
| TiO2 nanoparticles | 1535, 1700, 455 | Alkyl C-H, N h | 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 1535 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
-
Alkene (C=C) confidence 1.0
“LLM confirmed rule peak-group candidate”
Arizka 等 - 2019 - Synthesis and Physical Properties Characterization DOI: 10.1088/1757-899X/546/4/042004 -
Alkyl C-H confidence 1.0
“cm-1 and 1635 due to stretching vibrations of O-H group, the bands assigned at 3275 cmcm-1, - 1 the band at 2922 due to vibrations of C H stretching thee band at 1213 1062cm-1,482cm-1,576cm-1,1535cm-1arethefollowingvibrationsC-Ostretching,N”
Bio-engineered TiO2 nanoparticles using Ledebouria revoluta extract: Larvicidal, histopathological, antibacterial and anticancer activity DOI: 10.1080/03067319.2020.1718668 -
Aromatic ring confidence 1.0
“composites was endorsed by the appearance of (cm-1) in the FTIR spectra as follows: 625 peaks (α,α(cid:4)-coupling Polymerization of furan by MMT and formation of (C-H out-of-plane bending), 797 of the carbon backbone), 1018, 1063, 1158 (C-”
Preparation and evaluation of nanocomposites of polyfuran with Al2O3 and montmorillonite clay DOI: 10.1002/pi.1562 -
C c single bond confidence 1.0
“cm-1, which indicate C C the peaks at 1535and 1487 wileyonlinelibrary.com] stretching mode in quinoid ring and benzenoid ring, cm-1 respectively,[22]peaks at 1418and at 3361 appear TABLE 1 Peak position and ((cid:1))”
Dey Sadhu 等 - 2020 - Preparation and characterization of polyanilinea DOI: 10.1002/pc.25738 -
Fatty acid confidence 1.0
“cm-1, In agreement with some of the previous studies, we assign the peak at 1560 appearing at low fatty acid concentrations, to the adsorption of the carboxylate via a sodium counter-cation cm-1, while, the doublet peaking at 1535 and 1575”
Adsorption mechanisms of fatty acids on fluorite unraveled by infrared spectroscopy and first-principles calculations DOI: 10.1016/j.jcis.2020.09.062 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
JOONSUK - 2019 - ATR-FTIR Analysis of Adhesives Jointing Buddhist S DOI: 10.12654/JCS.2019.35.1.02 -
Acetate confidence 1.0
“Moreover peaks appearing at 160 1650cm-1 1535cm-1 and correspond to C=O stretching vibration and N-H deformation of 161 MBA respectively [26].”
Novel stimuli - responsive gellan gum - graft - poly(DMAEMA) hydrogel as adsorbent for anionic dye DOI: 10.1016/j.ijbiomac.2015.08.064 -
Silicon (Si) confidence 1.0
“The traces of the organic cm-1 materials from the PVP were at 1535 and 2787 and cm-1, are associated with Si-O stretching at 884, and 889 could be attributed to C-H bending vibrations [47, 48].”
Alibe 等 - 2019 - Effects of polyvinylpyrrolidone on structural and DOI: 10.1007/s10973-018-7874-7
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