What absorbs at 1302 cm⁻¹ in an FTIR spectrum?
A band near 1302 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 1302 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 | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| N-O bond | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Nitrate | 1 | 1 | 1.0 |
| C=n | 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 |
|---|---|---|---|
| polyurethane | 1302, 2270, 1700 | Amide | 1 |
| ZnO | 1302, 1400, 3430 | Amide | 1 |
| polyaniline | 1302, 1565, 1570 | Amide, Secondary amine, C n single bond | 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 1302 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
-
Carboxyl (COOH) confidence 1.0
“cm-1 cm-1, characteristic peaks at 1302 and 1416 which correspond to vibrational modes 3-) (COO-) of nitrate (NO and acetate ions [50,51].”
Sol-Gel Synthesized High Entropy Metal Oxides as High-Performance Catalysts for Electrochemical Water Oxidation DOI: 10.3390/molecules27185951 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Silkinspired polyurethane containing GlyAlaGlyAla tetrapeptide. II. physical properties and structure DOI: 10.1002/app.39185 -
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 -
Alkyl C-H confidence 1.0
“additional Raman bands of C-Cl vibrations in the lower wavenumber region at 636 and 695 The bands cm-1 cm-1 around 1302 and 1437 were assigned to the methylene groups.”
Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification DOI: 10.1038/s41598-022-23318-2 -
confidence 1.0
“The XPS spectrum intense doublets at 335.6 and 340.9 eV related to Pd(0) and of Mg 1s showed a peak at 1302 eV confirming the presence of peaks at 337.7 and 342 eV related to Pd(II) corresponding to Pd”
Palladium Nanoparticles on a Creatine‐Modified Bentonite Support: An Efficient and Sustainable Catalyst for Nitroarene Reduction DOI: 10.1002/cplu.201900377 -
N-O bond confidence 1.0
“The sharp peaks for nitro compounds (N-O cm-1 symmetricstretch)inthespectraofguarderivativesappearedrangingfrom1301.7503 cm-1 to 1367.5142 while for aromatics (C-C stretch in a ring) they only appeared in CGG cm-1) cm-1).”
Hydrolysis, Microstructural Profiling and Utilization of Cyamopsis tetragonoloba in Yoghurt DOI: 10.3390/fermentation9010045 -
Amide confidence 1.0
“carbohydrates ~1165 C-O vibration PO2- ~1238 Asymmetric vibration of ~1302 Amide III band”
Estimation of the age of human bloodstains under the simulated indoor and outdoor crime scene conditions by ATR-FTIR spectroscopy DOI: 10.1038/s41598-017-13725-1 -
Amide confidence 1.0
“The other 181 cm-1 characteristic bands at 1302, 1104, 792 and 697 can be attributed with the C-N stretching 182 of the secondary aromatic amine, aromatic C-H in-plane and out-of-plane bending, 183 cm-1”
Toumi 等 - 2022 - Synthesis of PANI@ZnO Hybrid Material and Evaluati DOI: 10.21203/rs.3.rs-661310/v1
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