What absorbs at 3396 cm⁻¹ in an FTIR spectrum?
A band near 3396 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 3396 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) | 10 | 9 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Protein | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Silicon hydride | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Urea | 1 | 1 | 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 |
|---|---|---|---|
| polyethylene | 3396, 1737, 1720 | Hydroxyl (O-H), Carboxyl (COOH) | 1 |
| HDPE | 3396, 1369, 1216 | Hydroxyl (O-H), Carboxyl (COOH) | 1 |
| PLA | 3396, 1650, 1073 | Carboxyl (COOH), Hydroxyl (O-H) | 1 |
| MWCNTs | 3396, 1735, 1610 | Carboxyl (COOH), 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 3396 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
-
Urea confidence 1.0
“The intercalation of and 3396 cm-1, corresponding to urea's functionalities.”
Potency of Urea-Treated Halloysite Nanotubes for the Simultaneous Boosting of Mechanical Properties and Crystallization of Epoxidized Natural Rubber Composites DOI: 10.3390/polym13183068 -
confidence 1.0
“- 0.6 sion2 1.49 N-H(cid:5)(cid:5)(cid:5)N stretching 3345 152 N-H stretching 3396”
Ay 和 Aydinli - 2004 - Comparative investigation of hydrogen bonding in s DOI: 10.1016/j.optmat.2003.12.004 -
confidence 1.0
“The infrared absorption peak of calcium sulfate precipitation mainly appearing at 3487 The infrared absorption peak of calcium sulfate precipitation mainly appearing at 3487 cm-1, cm-1 cm-1 3396 and the peak at 1681 are the stretching vibra”
Inhibition of Poly(ethylenediaminetetraacetic acid-diethanolamine) on Deposition of Calcium Sulfate Crystal in Simulated Industrial Water DOI: 10.3390/cryst10060544 -
confidence 1.0
“The cm-1 (cid:88)(cid:86)(cid:76)(cid:81)(cid:74)(cid:3)(cid:50)(cid:79)(cid:92)(cid:80)(cid:83)(cid:88)(cid:86)(cid:3)(cid:37)(cid:59)(cid:23)(cid:20)(cid:3)(cid:193)(cid:88)(cid:82)(cid:85)(cid:72)(cid:86)(cid:70)(cid:72)(cid:81)(cid:70)(”
El-Sheekh 和 El-Kassas - 2014 - Application of Biosynthesized Silver Nanoparticles DOI: 10.7314/APJCP.2014.15.16.6773 -
Hydroxyl (O-H) confidence 1.0
“The spectrum of MWCNTs exhibits characteristic peaks at 3396 and 2911 cm-1 represents -OH and C=O stretching vibrations of”
The Effect of MWCNTs Filler on the Absorbing Properties of OPEFB/PLA Composites Using Microstrip Line at Microwave Frequency DOI: 10.3390/ma13204581 -
Hydroxyl (O-H) confidence 1.0
“In addition, the broad band at 3396 cm-1, corresponding to the hydroxyl groups of pure cyclodextrin, appears sharper in the complex spectra, which is also proof of the complex's formation, observed by other researchers [27-29].”
Novel Chloro-Substituted Salicylanilide Derivatives and Their -Cyclodextrin Complexes: Synthesis, Characterization, and Antibacterial Activity DOI: 10.3390/biomedicines10071740 -
Silicon hydride confidence 1.0
“FTIR spectrum for the silane-treated composite reveals that the peaks at 792 cm-1, 1216 cm-1, 1369 cm-1, 1741 cm-1, and 3396 cm-1 have been eliminated in the silane treated HAp filler, which strongly confirms the chemical interaction betwee”
Physical and Mechanical Properties of Tilapia Scale Hydroxyapatite-Filled High-Density Polyethylene Composites DOI: 10.3390/polym14020251 -
confidence 1.0
“2, the broad peak near 3396 was the stretching vibration peak of the cm-1 N-H group participating in the hydrogen-bonding carbamate, while the peak at 2948 was the methylene stretching vibration.”
Jin 等 - 2021 - Preparation of Microspheres and Microfiber Membran DOI: 10.1002/app.39967
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