What absorbs at 1533 cm⁻¹ in an FTIR spectrum?
A band near 1533 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 1533 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 |
| N h | 8 | 8 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| Nitro (NO2) | 3 | 3 | 1.0 |
| Ring structure | 2 | 1 | 1.0 |
| Aromatic ring | 2 | 1 | 1.0 |
| Bronsted acid site | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Alkyl C-H | 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 |
|---|---|---|---|
| gelatin | 1533, 1652, 3300 | Amide, N h | 1 |
| nanoparticles | 1533, 1732, 1647 | Amide | 1 |
| chitosan | 1533, 1650, 1655 | Amide, N h | 1 |
| silver nanoparticles | 1533, 1636, 1631 | Amide, 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 1533 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-O bond confidence 1.0
“The peak at 1533 is caused by N-O stretching of aromatic nitro cm-1 compounds, the peak at 1386 is caused by symmetric carboxylate stretching, and the peak at 1327 is caused by N-O asymmetric stretching and reveals the presence of a nitro c”
Nematicidal activity of seaweed-synthesized silver nanoparticles and extracts against Meloidogyne incognita on tomato plants DOI: 10.1038/s41598-022-06600-1 -
Alkene (C=C) confidence 1.0
“ester composite of NCSAPP obtained superior peak at 1533 The XPS spectrum showed a fire-retardant properties than vinyl ester composites of CS and APP.”
Synthesis of a novel compound based on chitosan and ammonium polyphosphate for flame retardancy applications DOI: 10.1007/s10570-019-02671-y -
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 -
confidence 1.0
“The absorption peak at 1533 is due to deformation vibration of amino in amide II.”
Sang 等 - 2011 - Preparation and Application of Modified Soybean Pr DOI: 10.4028/www.scientific.net/AMR.139-141.706 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
De Anda-Flores 等 - 2020 - Covalently Cross-Linked Nanoparticles Based on Fer DOI: 10.3390/pr8060691 -
Amide confidence 1.0
“The main absorption bands for the gelatin are bration and bending vibration at 1533 Finally, C-N identified with various vibration methods of the peptide amide III is related to stretching vibration at cm-1 bond, which include amide A, amid”
Musa 等 - 2016 - Effect of Gelatin-Stabilized Copper Nanoparticles DOI: 10.1186/s11671-016-1656-6 -
Nitro (NO2) confidence 1.0
“The peak frequencies of cm-1 cm-1 cm-1 these bands are red-shifted upon cooling by 7 The band at 1533 (3087 is with all probability due to the nitro”
Low-Temperature FTIR Spectroscopic and Theoretical Study on an Energetic Nitroimine: Dinitroammeline (DNAM) DOI: 10.1021/jp711153g -
Amide confidence 1.0
“amide I band occurred at 1631 and the amide II band at 1533 The characcm-1 could be attributed to C-C asymmetric stretching, CH3 asymmetric rocking, and Ccm-1 cm-1 teristic absorption bands were also 1460 and 1414 (CH scissors vibration),”
Characterization and Combustion Behavior of Single-Use Masks Used during COVID-19 Pandemic DOI: 10.3390/ma14133501
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