What absorbs at 3363 cm⁻¹ in an FTIR spectrum?
A band near 3363 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 3363 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 8 | 8 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Urethane | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 0 | 1.0 |
| Silicon (Si) | 1 | 0 | 1.0 |
| Water (H2O) | 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 |
|---|---|---|---|
| lignin | 3363, 1035, 1510 | Hydroxyl (O-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 3363 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
-
Acetate confidence 1.0
“AC has characteristic spectra with a sharp absorption peak at 3373 Figure 3: FTIR spectra of (a) AC, (b) INA and (c) cm-1 indicating O-H stretching (free), aromatic NACINA cm-1, H stretching at 3363 C=O stretching at”
Wicaksono 等 - 2017 - Enhancement of solubility and dissolution rate of DOI: 10.4314/tjpr.v16i7.6 -
confidence 1.0
“The peak at 3363 was assigned to the hydrogen on coordination from N-H with carbonyl.”
Yusuf 等 - 2016 - From crab shell to solar cell a gel polymer elect DOI: 10.1039/C6RA04188D. -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Influence of Oxidation Degree on the Physicochemical Properties of Oxidized Inulin DOI: 10.3390/polym12051025 -
N h confidence 1.0
“The spectra differ mainly appearing stretching and bendcm-1, ing vibration, respectively at 3363, 1516 and 1612 which are corresponding to -NH groups originated from urethane bonds and starting isocyanates.”
Thermo-Chemical Decomposition Study of Polyurethane Elastomer Through Glycerolysis Route with Using Crude and Refined Glycerine as a Transesterification Agent DOI: 10.1007/s10924-016-0932-y -
confidence 1.0
“bands at 3459 and 3363 cm-1, assigned to stretching vibrations of amine and hydroxyl groups of The formation of hydrogen bonding can also be confirmed by consecutive changes in the”
Garbacz 等 - 2020 - Structural Characterization of Co-Crystals of Chlo DOI: 10.3390/pharmaceutics12070648 -
confidence 1.0
“Peaks observed at 3293 cm-1 cm-1 3293 and 3363 are indicative of the presence of the stretching vibrations of the amine group cm-1 and 3363 cm-1 are indicative of the presence of the stretching vibrations of the amine group in the”
Effect of the Zwitterion, p(MAO-DMPA), on the Internal Structure, Fouling Characteristics, and Dye Rejection Mechanism of PVDF Membranes DOI: 10.3390/membranes10110323 -
Hydroxyl (O-H) confidence 1.0
“0.12 O-H stretch (phenolics) 3384.45 3363.25 1052.94 0.14 3384.45cm-1 3363.25cm-1 (D.”
Goldson Barnaby 等 - 2016 - Characterization of Jamaican Delonix regia and Cas DOI: 10.1155/2016/3850102 -
Lignin confidence 1.0
“Purposed synthesis reactions of lignin based-hybrid polyurethanes FTIR spectra for lignin based on p-coumaryl alcohol, indicates some peaks at some wave numbers, such as 3363 cm-1 cm-1 cm-1”
International Conference on Innovation in Polymer Science and Technology DOI: 10.1088/1757-899X/223/1/012033
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.