What absorbs at 1760 cm⁻¹ in an FTIR spectrum?
A band near 1760 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 1760 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 |
|---|---|---|---|
| Carbonyl (C=O) | 16 | 12 | 1.0 |
| Methacrylate | 8 | 8 | 1.0 |
| Carboxyl (COOH) | 8 | 8 | 1.0 |
| Acetate | 8 | 8 | 1.0 |
| Ketone | 7 | 7 | 1.0 |
| Ester | 7 | 7 | 1.0 |
| Amide | 6 | 6 | 1.0 |
| Alkyl C-H | 6 | 6 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Adsorbed carbon monoxide | 2 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Aldehyde (CHO) | 1 | 1 | 0.9 |
| C#c | 1 | 1 | 0.7 |
| Carbonate | 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 |
|---|---|---|---|
| microplastics | 1760, 1643, 1614 | Carbonyl (C=O), Methacrylate, Acetate | 1 |
| PLGA | 1760, 3200, 1741 | Carbonyl (C=O), Methacrylate, Acetate | 1 |
| dentin | 1760, 575, 1740 | Methacrylate, Acetate, Carbonyl (C=O) | 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 1760 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
-
Carbonyl (C=O) confidence 1.0
“LLM confirmed rule peak-group candidate”
Poly(D, L-lactide-co-glycolide)/poly(ethylenimine) blend matrix system for pH sensitive drug delivery DOI: 10.1002/app.22636 -
confidence 1.0
“Similarly, a tassium content represents 6.3 wt %, the sulfur content cm(cid:1)1 peak at 1760 (CAO) appears at 346°C, the represents 4.8 wt %, the magnesium content reprecm(cid:1)1”
Zhang 等 - 2002 - Thermal properties of Bombyx mori silk fibers DOI: 10.1002/app.11089 -
Carbonyl (C=O) confidence 1.0
“plasma for 30 s showed a difference in the aromatic amines AR15 1.444589764 cm-1 (1250-1335 corresponds to the stretching vibration of C-N bond) and in the carbonyl stretch (around 1760 AR30 2.188986233 cm-1).”
Abreu 等 - 2016 - Effect of Non-Thermal Argon Plasma on Bond Strengt DOI: 10.1590/0103-6440201600914 -
Acetate confidence 1.0
“Fourier Transform Infrared Spectroscopy While C=O stretching bond, free acid band and C-O FTIR spectra of pure glipizide, Glutaric acid stretching at 1700 cm-1 , 1760 cm-1 and 1240 cm-1 and formulated GPZ-GLU cocrystals were examrespectivel”
Batool 等 - 2019 - USE OF GLUTARIC ACID TO IMPROVE THE SOLUBILITY AND DOI: 10.32383/appdr/94246 -
Alkyl C-H confidence 1.0
“From the figure it shows that JME 75% has indicated at 1760 The alkane bending -C-H vibration at 1460 cm-1.”
Fuel Analysis of Jatropha Methyl Ester and n-Tridecane as an Alternative Fuel for the Future DOI: 10.1051/matecconf/201815301002 -
Acetate confidence 1.0
“The C=O stretching (from ester linkage) was observed at 1760 cm-1, cm-1 the peak at 1457 was characterised by the CH band, the C-H deformation 3 cm-1.”
Boudjema 等 - 2020 - Green composites based on Atriplex halimus fibers DOI: 10.1515/polyeng-2020-0068 -
Ester confidence 1.0
“LLM confirmed rule peak-group candidate”
Bratu 等 - 2009 - Inclusion compound of Fosinopril with beta-cyclode DOI: 10.3233/SPE-2009-0373 -
Carboxyl (COOH) confidence 1.0
“drocarbons and degradation products containing a C=O stretching bond at 1260 cm-1 through deoxygenation reactions of O-H stretching, mainly originating from its own oxygen atoms at 3583 cm-1 and benzoate carboxylic acid at 1760 cm-1.”
Pyrolysis Process of Mixed Microplastics Using TG-FTIR and TED-GC-MS DOI: 10.3390/polym15010241
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