What absorbs at 3404 cm⁻¹ in an FTIR spectrum?
A band near 3404 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 3404 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) | 13 | 13 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Phenolic | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Protein | 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 | 3404, 1650, 1655 | Alkyl C-H, Hydroxyl (O-H), N h | 1 |
| Fe3O4 | 3404, 2358, 1673 | Hydroxyl (O-H), Alkyl C-H, N h | 1 |
| cotton | 3404, 1030, 1638 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| bentonite | 3404, 882, 918 | 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 3404 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
“7b, the bands detected at 3404 and 3314 were identified as belonging to O-H cm-1 stretching vibrations, while the bands located at lower wavelengths of 1804 were mainly ascribed to out-of-plane stretching vibrations, implying that using onl”
Ibrahim 等 - 2023 - Role of ammonium phosphate in improving the physic DOI: 10.37190/ppmp/161510 -
Alkyl C-H confidence 1.0
“1223 and 1364 (C(CH 3) 3), 1438, 1509, 1596, 1611, 2962, 3026 (C-H stretching vibration), 3404 (O-H telescopic (1H-NMR;”
Synthesis and properties of soluble polyimides containing tert-butyl, ether linkages, and triphenylmethane units DOI: 10.1177/0954008320906602 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Shareef 和 Bhavya - 2021 - Extraction, phytochemical analysis and in silico a DOI: 10.21276/ap.2021.10.2.59 -
Hydroxyl (O-H) confidence 1.0
“fiber fiber cm-1, chains in from being tender severely and prevented the O-H a broad peak at 3404 which has been attributed to cm-1 (Wang et al., 2015).”
Singh 等 - 2017 - Sustainable fragrance cum antimicrobial finishing DOI: 10.1016/j.scp.2017.01.003 -
Hydroxyl (O-H) confidence 1.0
“from 20 minutes' contact time to 120 minutes for both 4 3615cm-1 The band at was due to O-H stretching, and a granules is due to the fact that initially all adsorbent sites 3404cm-1 broad band centered on was due to the interlayer”
Annan 等 - 2021 - Synthesis and Characterization of Modified Kaolin- DOI: 10.1155/2021/6679422 -
Alkene (C=C) confidence 1.0
“poly(vinyl) alcohol and savlon, as evident from cm-1 the peaks observed at 3449 and 3404 cm-1 respectively.29 The spectra (Fig.”
Chhatri 等 - 2011 - Designing polysaccharide-based antibacterial bioma DOI: 10.4161/biom.1.2.19005 -
Hydroxyl (O-H) confidence 1.0
“Also, bands at 3404 and 1653 are related to vibrations of OH respectively36.”
Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr (VI) ions DOI: 10.1038/s41598-021-96145-6 -
confidence 1.0
“cm-1 43respectively.26 PO , The sharp absorption peak at 3404 Besides, we designed another experiment to exclude the N-H ring.27 is the result of the vibration of in the indole The”
Geng 等 - 2021 - Facile Fabrication of a Novel Copper Nanozyme for DOI: 10.1021/acsomega.0c05925
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.