What absorbs at 3356 cm⁻¹ in an FTIR spectrum?
A band near 3356 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 3356 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) | 5 | 5 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Ammonium | 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 |
|---|---|---|---|
| chitosan | 3356, 1650, 1655 | Alkyl C-H, Hydroxyl (O-H), N h | 1 |
| Nanocellulose | 3356, 1540, 1646 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| nanoparticles | 3356, 1732, 1647 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| lignin | 3356, 1035, 1510 | Alkyl C-H, Lignin, 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 3356 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
-
Ammonium confidence 1.0
“cm-1 are assigned to s(NH 3) coordinated to Lewis and 3255 (cid:238) last peak may be assigned to either as(NH 3) coordinated to (cid:228) cm-1 acid sites, and the band at 3356 is assigned to as(NH 3) (cid:238) Lewis acid sites or possibly”
Pena 等 - 2004 - Identification of surface species on titania-suppo DOI: 10.1021/jp0313122 -
confidence 1.0
“Peaks at 3332 cm-1 3356 showed the N-H stretching peak assigned to monopeptides or dipeptides [9].”
Wei 等 - 2014 - An Optimization Study on the Inclusion of Aluminiu DOI: 10.4028/www.scientific.net/AMR.844.399 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Gao 等 - 2020 - Structures, Properties and Potential Applications DOI: 10.3390/polym12030638 -
Lignin confidence 1.0
“The peaks were detected at 3355 for standard cm-1 cm-1, cm-1 lignin, 3347 for isolated lignin, and 3327 and 3356.47 for L-MeOH and 3347 cm-1 for isolated lignin, and 3327 cm-1, and 3356.47 cm-1 for L-MeOH and L-Ac, recm-1 L-Ac, respectively”
Enhancing Thermal and Mechanical Properties of Ramie Fiber via Impregnation by Lignin-Based Polyurethane Resin DOI: 10.3390/ma14226850 -
confidence 1.0
“cm-1, of the O-H and N-H stretching were recorded at 3356 At 2870 the peak of CH stretching 2 vibration was recorded, which corresponded to the C-6 of the pyranose ring.”
Islam 等 - 2019 - In Vitro Enzymatic Digestibility of Glutaraldehyde DOI: 10.3390/molecules24071271 -
Hydroxyl (O-H) confidence 1.0
“Peaks corresponding to cm-1) cm-1) O-H groups (3356 and the stretching vibrations of C-H (2956 were observed.”
APTES-Modified Nanocellulose as the Formaldehyde Scavenger for UF Adhesive-Bonded Particleboard and Strawboard DOI: 10.3390/polym14225037 -
Hydroxyl (O-H) confidence 0.9
“Broad peaks at 3356 cm-1 attributed to hydroxy groups.”
Zhu 等 - 2021 - Formation and characterization of furfuryl mercapt DOI: 10.2478/pjct-2021-0035 -
Hydroxyl (O-H) confidence 0.8
“Broad band at 3356 due to O-H groups.”
Yalcin 和 Gonen - 2021 - A novel approach for the production of zinc borate DOI: 10.1515/mgmc-2021-0001
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