What absorbs at 1361 cm⁻¹ in an FTIR spectrum?
A band near 1361 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 1361 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 | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 3 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Carbonate | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Nitrate | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 0.7 |
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 |
|---|---|---|---|
| PMMA | 1361, 1722, 1383 | Methacrylate, Acetate, C-O single bond | 1 |
| TiO2 | 1361, 1700, 1093 | Methacrylate, Acetate, C-O single bond | 1 |
| CeO2 | 1361, 1554, 1630 | Acetate, Methacrylate, C-O 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 1361 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
-
Alkyl C-H confidence 1.0
“The observed cm-1 cm-1 1361 (amide, -CN-) aliphatic absorption peaks and 1626 (>C=O) amino acid cysteine absorption peaks were typical effects of external factors on polypeptide hair fibers.”
Chang 等 - 2017 - Material Characteristics of Hair Cuticles after Ha DOI: 10.18494/SAM.2017.1707 -
Alkyl C-H confidence 1.0
“Further, the cm-1 cm-1 doublet characteristic peaks 1361 and 1339 of the CH wagging mode merged 2 cm-1 into a single peak which appeared at 1360 confirming that the PEO crystallite phase”
Effects of different inorganic nanoparticles on the structural, dielectric and ion transportation properties of polymers blend based nanocomposite solid polymer electrolytes DOI: 10.1016/j.electacta.2017.07.051 -
C-O single bond confidence 1.0
“The absorption peaks including aromatic C-H deformation at 670 cm-1, C-O stretching at 1052 cm-1, phenolic C-OH stretching at 1200 cm-1, C-OH at 1361 cm-1, hydroxyl groups of molecular water and C=C at 1625 cm-1,”
Influence of Sputtering Temperature of TiO2 Deposited onto Reduced Graphene Oxide Nanosheet as Efficient Photoanodes in Dye-Sensitized Solar Cells DOI: 10.3390/molecules25204852 -
confidence 1.0
“Notable bands at 1578cm-1, 1562cm-1 may be assigned to O-C-O stretching or N -coordination through alkaloids 1474cm-1, 1370cm-1 1361cm-1 and ascribed to -O-O-H stretching in the extract Bands at”
Synthesis of nanostructured CeO2 by chemical and biogenic methods: Optical properties and bioactivity DOI: 10.1016/j.ceramint.2020.02.204 -
Acetate confidence 1.0
“The vibration bands of carbonate anions were were produced from gelatin combustion during the chemical processing-similar results cm-1 depicted by the stretching vibration of C-O at 1361 [41].”
Synthesis of CaCO3/Cu2O/GO Nanocomposite Catalysts for Hydrogen Production from NaBH4 Methanolysis DOI: 10.3390/catal13061010 -
Hydroxyl (O-H) confidence 1.0
“The in-plane bending vibration peak of the O-H bond is 1361 1122 -CH2-.”
Inhibition of Poly(ethylenediaminetetraacetic acid-diethanolamine) on Deposition of Calcium Sulfate Crystal in Simulated Industrial Water DOI: 10.3390/cryst10060544 -
Fatty acid confidence 1.0
“cm-1 1357 and 1361 cm-1 cm-1 cm-1 1260 -1300 1298 for Fatty acids cm-1 for major peaks of for α-helix”
Exosomes isolated from two different cell lines using three different isolation techniques show variation in physical and molecular characteristics DOI: 10.1101/2020.06.06.122952 -
Alkyl C-H confidence 1.0
“Signals obtained at 1311 are assigned to C=O vibration in lignin and at 1361 associated to deformation of C-H group in cellulose and hemicellulose.”
Diego Mendez-Mejias 和 Moya - 2016 - Effects on density, shrinking, color changing and DOI: 10.18671/scifor.v44n112.03
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