What absorbs at 3465 cm⁻¹ in an FTIR spectrum?
A band near 3465 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 3465 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 | 7 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Sulfur | 1 | 1 | 0.7 |
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 |
|---|---|---|---|
| CNTs | 3465, 2941, 532 | Hydroxyl (O-H), Carboxyl (COOH) | 1 |
| zinc oxide | 3465, 1627, 1638 | Carboxyl (COOH), Amide | 1 |
| zinc oxide nanoparticles | 3465, 1744, 1627 | Hydroxyl (O-H), Carboxyl (COOH), Amide | 1 |
| silver nanoparticles (AgNPs) | 3465, 1100, 1749 | Amide, Hydroxyl (O-H), Carboxyl (COOH) | 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 3465 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
-
Amide confidence 1.0
“Morphological Analysis The spectra of diazo Congo red dye exhibited a peak for the N-H stretching vibraIn this work, the morphological characteristics of PFSS were investigated by SEM, tions of secondary amide at 3465 cm-1.”
Degradation of Diazo Congo Red Dye by Using Synthesized Poly-Ferric-Silicate-Sulphate through Co-Polymerization Process DOI: 10.3390/polym15010237 -
Hydroxyl (O-H) confidence 1.0
“of CP-AgNPs showed the presence of an O-H functional group cm-1, with a broad band at 3464.94 while the IR spectrum of CPFigure 4.”
Bello 等 - 2020 - Phytobiological-facilitated Production of Silver N DOI: 10.4274/tjps.galenos.2019.10846 -
Hydroxyl (O-H) confidence 1.0
“The spectra cm-1 ance of the strong O-H band at 3465 and significant of ELO and polymerized ELO were measured by distributing a film”
Jebrane 等 - 2015 - Novel hydrophobization of wood by epoxidized linse DOI: 10.1515/hf-2014-0030. -
Hydrogen bond confidence 1.0
“hydrogen-bonding between the -OH in the Ca nodes and aqua, After adsorption of fluoride, the cm-1 stretching of -OH group at 3465 is remarkably diminished and the -OH stretch of the hydrogen-bonding cm-1 based at 2745 disappeared completely”
Fumarate-based metal-organic frameworks as a new platform for highly selective removal of fluoride from brick tea DOI: 10.1038/s41598-018-19277-2 -
Hydroxyl (O-H) confidence 1.0
“The strong peaks at 3465 and 1640 in O-CNTs and N-CNTs can be assigned to the stretching vibration of the O-H and C=O groups.”
Li 等 - 2022 - Effect of pH-Dependent HomoHeteronuclear CAHB on DOI: 10.3390/ijerph191912118 -
confidence 1.0
“A peak at about 3465 that was assigned to N-H overlapped with a stretching vibration of hydroxyl groups (-OH) in the sample spectra.”
Mansour 等 - 2022 - Green Synthesis of Zinc Oxide Nanoparticles Using DOI: 10.3390/ma15155169 -
Hydroxyl (O-H) confidence 1.0
“cm-1 OH--, DS--, DBS-- broad band centered at around 3440, 3455, and 3465 in and broad band centered at around 3440, 3455, and 3465 cm-1 in OH--, DS--, and DBS--intercaintercalated Li-Al LDH, respectively, arise from the O-H stretching mode”
Surfactant Intercalation in Li-Al-Based Binary and Ternary Layered Double Hydroxides by the Microwave-Assisted Rapid Ion-Exchange Process and Its Application in Iodine Adsorption DOI: 10.3390/min13030303 -
confidence 1.0
“IR spectrum for CBZ has two characteristic peaks at 3465, 1675 which correspond to the stretching of amine (NH 2) and carbonyl (C=O) group of CBZ.”
Zhang 等 - 2017 - Preparation and Characterization of Carbamazepine DOI: 10.3390/pharmaceutics9040054
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