What absorbs at 3697 cm⁻¹ in an FTIR spectrum?
A band near 3697 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 7 cited sources
Quick answer
A band near 3697 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.
Mögliche Funktionsgruppenzuweisungen
| Funktionelle Gruppe | Unterstützende Fakten | Zitierte Quellen | Höchstes Vertrauen |
|---|---|---|---|
| Hydroxyl (O-H) | 7 | 7 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
Das Ranking spiegelt die gesammelte Literatur Evidenz wider, nicht eine einzelne maßgebliche Regel. Bestätigen Sie immer anhand Ihres Probenkontexts.
Possible materials
| Material | Unterstützende Peaks | Overlapping groups | Zitierte Quellen |
|---|---|---|---|
| silica | 3697, 1100, 1080 | Silicon-oxygen (Si-O), Silicon (Si), Hydroxyl (O-H) | 1 |
| montmorillonite | 3697, 1637, 523 | Hydroxyl (O-H), Silicon-oxygen (Si-O), Silicon (Si) | 1 |
| kaolinite | 3697, 3696, 693 | Hydroxyl (O-H), Silicon-oxygen (Si-O), Silicon (Si) | 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 3697 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.
Literatur hinter diesen Zuweisungen
-
Hydroxyl (O-H) Vertrauen 1,0
“Pt/silicad 3697/3676 O-H stretch of isolated silanol 3673 3740 silicaf 3515 3535/3509 O-H stretch of silanol H-bonded to 3510”
Leewis 等 - 2006 - Ammonia adsorption and decomposition on silica sup DOI: 10.1016/j.apsusc.2005.12.115 -
Hydroxyl (O-H) Vertrauen 1,0
“mixed-layered phases in the XRD patterns of the untreated samples reflection O-H-stretching was manifested by a strong and broad between 13Å and The soil clay FTIR spectra contain bands at 3697cm-1 cm-1 and 3653 assigned to kaolinite in add”
The nature of interlayering in clays from a podzol (Spodosol) from the Tatra Mountains, Poland DOI: 10.1016/j.geoderma.2010.10.013 -
Hydroxyl (O-H) Vertrauen 1,0
“The extracted strongest absorption band at ~3697cm-1 were assigned to OH-stretching in the octahedral at solution was then separated from the clay fraction residue by sheet of aluminous minerals such as illite or kaolinite (Farmer centrifug”
Characterisation of the hydroxy-interlayered vermiculite from the weathering of illite in Jiujiang red earth sediments DOI: 10.1071/SR14014 -
Hydroxyl (O-H) Vertrauen 1,0
“(cm-1) Assignments Wavenumber 3697 O-H stretching”
Caccamo 等 - 2020 - Self-Assembly Processes in Hydrated Montmorillonit DOI: 10.3390/ma13051100 -
Hydroxyl (O-H) Vertrauen 1,0
“LLM confirmed rule peak-group candidate”
Negrao 等 - 2021 - Mineralogical Appraisal of Bauxite Overburdens fro DOI: 10.3390/min11070677 -
Hydroxyl (O-H) Vertrauen 1,0
“The major cm-1 band at 3697.36 is due to the antisymmetric stretching vibration of the O-H band [18].”
Preparation of Mg(OH)2/Calcined Fly Ash Nanocomposite for Removal of Heavy Metals from Aqueous Acidic Solutions DOI: 10.3390/ma13204621 -
Hydroxyl (O-H) Vertrauen 0,9
“Stretch bands of OH group characteristic of kaolinite.”
Hildebrando 等 - 2014 - Synthesis and Characterization of Zeolite NaP Usin DOI: 10.1590/S1516-14392014005000035
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