What absorbs at 3657 cm⁻¹ in an FTIR spectrum?
A band near 3657 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 3657 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.
Iespējamie funkcionālo grupu piešķīrumi
| Funkcionālā grupa | Atbalstošie fakti | Citētie avoti | Augstākā pārliecība |
|---|---|---|---|
| Hydroxyl (O-H) | 2 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 0,9 |
Rangs atspoguļo uzkrātos literatūras pierādījumus, nevis vienu autoritatīvu noteikumu. Vienmēr apstipriniet atbilstoši parauga kontekstam.
Possible materials
| Materiāls | Atbalstošie pīķi | Overlapping groups | Citētie avoti |
|---|---|---|---|
| water | 3657, 1018, 2945 | Hydroxyl (O-H), Water (H2O) | 2 |
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 3657 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.
Literatūra aiz šiem piešķīrumiem
-
Amide pārliecība 1,0
“For example, in the 1682(+)/1672(-) stretching region (Figure 2d), signals were observed at amide I region, peaks at diminished and 3657(-)/3646(+), 3636(-)/3624(+), 3599(+)/3590(-) 1676(+)/1664(-), and were replaced by a small signal at wh”
Takahashi 等 - 2007 - Water molecules coupled to the redox-active tyrosi DOI: 10.1021/bi701752d -
Water (H2O) pārliecība 1,0
“cm-1, Corresponding bands are observed in H at 3657, 3645 and 3634 respectively, - P showing that these bands arise from water O-H stretching vibrations.”
Morgan 等 - 2007 - Water structural changes in the L and M photocycle DOI: 10.1021/bi0616596. -
Carboxyl (COOH) pārliecība 0,9
“Explicit assignment: 'peaks at 3657, 2651, and 2559 indicate the peak of -COOH'”
Influence of gamma irradiation on rosin properties and its antimicrobial activity DOI: 10.1038/s41598-023-31372-7
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