What absorbs at 3381 cm⁻¹ in an FTIR spectrum?
A band near 3381 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 3381 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 |
| Water (H2O) | 2 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Oxygen heterocycle | 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 |
|---|---|---|---|
| quartz | 3381, 800, 3053 | Silicon-oxygen (Si-O), Hydroxyl (O-H), Metal hydroxyl | 1 |
| silver nanoparticles | 3381, 1636, 1631 | 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 3381 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
“LLM confirmed rule peak-group candidate”
Kamarulzaman 和 Tahir - 2017 - The Effect of Isocyanate Structure on Ionic Conduc DOI: 10.1063/1.5002441 -
confidence 1.0
“stephensi that had LC values of 55.13, 50 cm-1), N-H C-H groups, namely stretch (3381.28 stretch 58.81, 75.66, and 94.31 and 81.47, 92.09, 96.07, 101.31 mg/ cm-1), cm-1), 3-C-H (2921.03 C=C stretch (1640.17 CH”
Santhosh 等 - 2015 - Annona muricata leaf extract-mediated silver nanop DOI: 10.1007/s00436-015-4511-2 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Suhalim 等 - 2023 - Impact of Silver-Decorated Graphene Oxide (Ag-GO) DOI: 10.3390/membranes13060602 -
Silicon (Si) confidence 1.0
“The bands observed at 3190 The less intense bands at 449, 496, 582, 678, and 725cm-1 and 3310 are attributed to Si-O stretching, the bands at are attributed to Si-O bending and some bands 3379cm-1 3381cm-1 mightbeduetoCa-Ostretchingvibratio”
Ahmad 等 - 2021 - Spectroscopic Analysis for Harnessing the Quality DOI: 10.1155/2021/6629640 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Ayu 等 - 2020 - The Production of Nanocrystalline Cel close From O DOI: 10.1063/5.0015667 -
Water (H2O) confidence 1.0
“The infrared spectra of 1 and 2 featured absorption bands due to the OH groups 1 2 The infrared spectra of and featured absorption bands due to the OH groups from cm-1, from the water ligands in the stretching vibration region of 3500-3000”
Structural and Thermal Investigations of Co(II) and Ni(II) Coordination Polymers Based on biphenyl-4,4'-dioxydiacetate Linker DOI: 10.3390/ma14133545 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Wang 等 - 2018 - Developing Effective Separation of Feldspar and Qu DOI: 10.3390/min8040149 -
confidence 0.9
“Text: 'scaled value at cm-1 3550 is assigned to the asymmetric stretching vibration NH which is observed in IR at 3381'”
Sreedevi 等 - 2023 - GROWTH, CHARACTERIZATION AND CHEMICAL COMPUTATIONS DOI: 10.4314/bcse.v37i4.18
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