What absorbs at 3365 cm⁻¹ in an FTIR spectrum?
A band near 3365 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 3365 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 | 10 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Carbohydrate | 3 | 3 | 1.0 |
| Hydrogen bond | 2 | 2 | 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 |
|---|---|---|---|
| cellulose | 3365, 1735, 1650 | Hydroxyl (O-H), Carbohydrate | 1 |
| HCl | 3365, 1708, 1032 | Hydroxyl (O-H), N h, Carbohydrate | 1 |
| polymer | 3365, 1718, 1722 | Hydroxyl (O-H) | 1 |
| nanoparticles | 3365, 1732, 1647 | 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 3365 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
-
Hydroxyl (O-H) confidence 1.0
“a b from trace to reveals a sudden decrease in the intensity of 3238cm-1, the peak at which corresponds to the O-H symmetric stretch for pure water ice, and the gradual appearance 3365cm-1.”
Chiesa 和 Rossi - 2013 - The metastable HCl center dot 6H(2)O phase - IR sp DOI: 10.5194/acp-13-11905-2013 -
confidence 1.0
“FTIR study The comparison of FTIR spectra of prepared BCS@Ag-NPs Bunium persicum with the alcoholic BCS-extract of revealed cm-1 that band at 3365 corresponded to the hydroxyl functional group region of phenol, alcohol or amine.”
Khan 等 - 2022 - Synthesis, biological investigation and catalytic DOI: 10.1007/s40097-021-00402-z -
confidence 1.0
“(cm-1) Functional group Wavelength (s, N-H (stretch)) 3460 (s, N-H (stretch)) 3365”
Mohamad 等 - 2017 - Synthesis and Characterization of Methyl 4-(4-Amin DOI: 10.1063/1.5002299 -
N h confidence 1.0
“LLM confirmed rule peak-group candidate”
Raman 等 - 2017 - Preparation and Characterization of Impregnated Co DOI: 10.1088/1757-899X/206/1/012005 -
Hydroxyl (O-H) confidence 1.0
“Peaks at 3365 out cm-1 cm-1 ∼122 namic size of skimmed milk is found to be nm which is due O H stretching), 1722 (for C O stretching), 1652 cm-1 to the presence of casein micelles [49-51].”
The interaction, stability and response to an external stimulus of iron oxide nanoparticle–casein nanocomplexes DOI: 10.1016/j.colsurfa.2012.04.049 -
N h confidence 1.0
“Explicit assignment: 'assigned to -NH stretching'”
Shoaib 和 Bahadur - 2016 - Synthesis of thermally and mechanically improved p DOI: 10.1515/epoly-2016-0134 -
Hydrogen bond confidence 1.0
“The F2 and F3 formulated films were showed drug and polymer interacted with hydrogen bonding to broad peak at 3328 and 3365 cm -1 that was assigned to enable the drug to release quickly and may aim for rapid O-H stretching vibration for the”
AnjiReddy 和 Karpagam - 2020 - Micro and nanocrystalline cellulose based oral dis DOI: 10.1590/s2175-97902020000117797 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Structural Studies of the Cutin from Two Apple Varieties: Golden Delicious and Red Delicious (Malus domestica) DOI: 10.3390/molecules25245955
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