What absorbs at 3618 cm⁻¹ in an FTIR spectrum?
A band near 3618 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 3618 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.
Attributions possibles de groupes fonctionnels
| Groupe fonctionnel | Faits à l＇appui | Sources citées | Confiance maximale |
|---|---|---|---|
| Hydroxyl (O-H) | 4 | 4 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| Metal hydroxyl | 1 | 1 | 0,8 |
Le classement reflète les preuves bibliographiques accumulées, et non une règle faisant autorité. Confirmez toujours dans le contexte de votre échantillon.
Possible materials
| Matériel | Pics de support | Overlapping groups | Sources citées |
|---|---|---|---|
| oil shale | 3618, 1625, 1053 | Alkyl C-H, 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 3618 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.
Bibliographie derrière ces attributions
-
Alkyl C-H confiance 1,0
“cm-1 C-H in the Peaks at 3618 and 3709 are Kaolinite[12,26].”
Zhao 等 - 2015 - Evaluation of Oil Yield of Oil Shale by Infrared S DOI: 10.1007/s40242-015-4364-3 -
confiance 1,0
“[36] 2011 Al-Fe-OH the symmetric stretching bands at 3324 and 3618 cm-1 correspond to and 3445-3440 Zeoliticwater”
Benjamin Ortega-Lazcano 等 - 2021 - Study of Pigments from the Colonial Convent of Act DOI: 10.3390/min11080852 -
confiance 1,0
“This latter amphibole indeed represents a reference point 3618 cm-1, whose relative intensities are correlated with the Mg/Fe2+ ratio at M(1,3).”
Della Ventura 等 - 2018 - Infra Red Spectroscopy of the Regulated Asbestos A DOI: 10.3390/min8090413 -
Hydroxyl (O-H) confiance 1,0
“LLM confirmed rule peak-group candidate”
Morphology and Selected Properties of Modified Potato Thermoplastic Starch DOI: 10.3390/polym15071762 -
Alkyl C-H confiance 1,0
“and 3618 The peak related to the asymmetric stretching vibration of methylene at cm-1 2920 [40] was clearly visible in all techniques, while the peak related to the symmetric cm-1 stretching vibration of aliphatic methylene at 2850 [26] was”
Application of FTIR-PAS in Rapid Assessment of Rice Quality under Climate Change Conditions DOI: 10.3390/foods10010159 -
Hydroxyl (O-H) confiance 0,95
“Text: 'peak at ν = 3618 is due to OH stretching frequencies'”
Microsoft Word - Finished - Mineral Identification of Rocks From Pohon Batu Hot Springs in West Seram Using FTIR Spectroscopy DOI: 10.1088/1742-6596/1572/1/012045 -
Hydroxyl (O-H) confiance 0,8
“Assigned to stretching vibration of hydroxyl groups.”
Multi-Method Analysis of Painting Materials in Murals of the North Mosque (Linqing, China) DOI: 10.3390/coatings13071298
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