What absorbs at 3639 cm⁻¹ in an FTIR spectrum?
A band near 3639 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 3 cited sources
Quick answer
A band near 3639 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.
Possibili assegnazioni di gruppi funzionali
| Gruppo funzionale | Fatti di supporto | Fonti citate | Affidabilità massima |
|---|---|---|---|
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 0 | 1,0 |
La classifica riflette le prove bibliografiche accumulate, non una singola regola autorevole. Conferma sempre nel contesto del tuo campione.
Possible materials
| Materiale | Picchi di supporto | Overlapping groups | Fonti citate |
|---|---|---|---|
| CaCO3 | 3639, 1141, 712 | Water (H2O), Hydroxyl (O-H), Silicon-oxygen (Si-O) | 1 |
| CaO | 3639, 2909, 1839 | Hydroxyl (O-H), Silicon-oxygen (Si-O), Water (H2O) | 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 3639 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.
Letteratura dietro queste assegnazioni
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affidabilità 1,0
“cm-1 cm-1 cm-1 brations at 3639 cm-1 for -OH, 2860 cm-1 for -C-H, 2487 cm-1 for -C≡C-, 1625 cm-1 for -N-H, -C≡C-, vibrations at 3639 for -OH, 2860 for -C-H, 2487 for 1625 for cm-1 cm-1 cm-1 for -COOH, 1053 cm-1 for -C-F, and 530 cm-1 for Ca”
Biosynthesis and Characterization of Calcium Oxide Nanoparticles from Citrullus colocynthis Fruit Extracts; Their Biocompatibility and Bioactivities DOI: 10.3390/ma16072768 -
Hydroxyl (O-H) affidabilità 1,0
“The hydroxyl stretch regions for octahedra and rods look cm(cid:2)1 quite similar, showing a strong band at 3639 for bridging cm(cid:2)1 hydroxyls, with a shoulder at 3669 arising from single-co-”
Exposed Surfaces on ShapeControlled Ceria Nanoparticles Revealed through ACTEM and WaterGas Shift Reactivity DOI: 10.1002/cssc.201300651 -
Hydroxyl (O-H) affidabilità 1,0
“The absorption peak cm-1 at 3639.02 has also resulted due to the O-H bond from water molecules on the surface of the cm-1 nanoparticle [18,24].”
Habte 等 - 2019 - Synthesis of Nano-Calcium Oxide from Waste Eggshel DOI: 10.3390/su11113196
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