What absorbs at 2361 cm⁻¹ in an FTIR spectrum?
A band near 2361 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 2361 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 |
|---|---|---|---|
| Methacrylate | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Carbon dioxide | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Hydrogen bond | 2 | 0 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| C#c | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.7 |
| Nitrile | 1 | 1 | 0.5 |
| Hydroxyl (O-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 |
|---|---|---|---|
| AgNPs | 2361, 1232, 1048 | Methacrylate, Acetate | 2 |
| chitosan | 2361, 1650, 1655 | Acetate, Methacrylate | 1 |
| gold nanoparticles | 2361, 1638, 3252 | Methacrylate, Acetate | 1 |
| silver nanoparticles | 2361, 1636, 1631 | Methacrylate, Acetate | 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 2361 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
-
Chitosan confidence 1.0
“A signal at 1737 on chitosan spectrum was attributed to the carboxylic (C=O) groups T 2361cm-1 overlapped by MPEO incorporation.”
Mentha piperita essential oils loaded in a chitosan nanogel with inhibitory effect on biofilm formation against S. mutans on the dental surface DOI: 10.1016/j.carbpol.2019.02.018 -
Carboxyl (COOH) confidence 1.0
“cm-1 spectra of samples calcined at 750, 850, 950 and The peaks observed near 2361 for temperatures 1050°C 2less than can be attributed to the vibration band of - CO related to the citric acid.”
Carol 等 - 2017 - Effect of Temperature on the Magnetic Properties o DOI: 10.1063/1.4990307 -
confidence 1.0
“The peak at 2360.7 represents the N-H stretching vibration or C=O MANUSCRIPT stretching vibration of amine groups representing the presence of peptides as capping and stabilisation molecules in the synthesis of Ag-NPs [40].”
Kumar 等 - 2017 - Photo-induced and phytomediated synthesis of silve DOI: 10.1016/j.jphotobiol.2017.04.022 -
Phosphate (PO4) confidence 1.0
“ATD-FTIR spectra of the Salisbury's patina exhibit peaks at 2361, 2341 and 671 cm-1 (assigned to phosphates);”
Martin-Gil 等 - 2005 - The orange-brown patina of Salisbury Cathedral (We DOI: 10.1065/espr2005.05.257 -
confidence 1.0
“The cm-1 peak at 2361 could be assigned to N-H stretching or C-O stretching vibrations (Ashok et al.”
Biogenic silver nanoparticles: efficient and effective antifungal agents DOI: 10.1007/s13204-015-0463-1 -
Alkyl C-H confidence 1.0
“Furthermore, the peak at 2920.32 is ascribed to C-H cm-1 which is likely to correspond to C≡C stretch of the alkyl group, the peak around 2360.95 cm-1 from alkyne and the peak at 1635.69 suggested conjugation effects of C=O stretching of ca”
Oladipo 等 - 2020 - Characterization and biomedical application of phy DOI: 10.1088/1757-899X/805/1/012021 -
Carbon dioxide confidence 1.0
“First, gas phase CO2 filled the cell, as indicated by the bands at 2361”
Thermal and Plasma-Assisted CO2 Methanation over Ru/Zeolite: A Mechanistic Study Using In-Situ Operando FTIR DOI: 10.3390/catal13030481 -
confidence 1.0
“According to [4, 22], the empirical to indicates that loss parameter, R, is defined as the ratio of the height of the (002) of hydrogen and oxygen atoms due to the breaking bond 2361cm1 Bragg reflection to that of background and is a measur”
Armynah 等 - 2019 - Potentials of Biochars Derived from Bamboo Leaf Bi DOI: 10.1155/2019/3526145
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