What absorbs at 1756 cm⁻¹ in an FTIR spectrum?
A band near 1756 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 6 cited sources
Quick answer
A band near 1756 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.
Möjliga identifieringar av funktionella grupper
| Funktionell grupp | Stödjande fakta | Citerade källor | Högsta förtroende |
|---|---|---|---|
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Amide | 3 | 3 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Ketone | 2 | 2 | 1,0 |
| Ester | 2 | 2 | 1,0 |
| Carboxyl (COOH) | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Methyl | 1 | 1 | 1,0 |
| N-O bond | 1 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.
Possible materials
| Material | Stödjande toppar | Overlapping groups | Citerade källor |
|---|---|---|---|
| gelatin | 1756, 1652, 3300 | Amide, Methacrylate, Alkyl C-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 1756 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.
Litteratur bakom dessa identifieringar
-
N h förtroende 1,0
“In the asynchronous 3228)cm(cid:2)1can map,one negativecrosspeakat(3317, beobserved, The appearance of crosspeaks at B(1756, 1712) and E(1712, 3339cm(cid:2)1 1689)cm(cid:2)1showsthatthe cm(cid:2)1in1D-IR n(NH)b which indicates that the band”
Sun 等 - 2008 - Innovative spectral investigations on the thermal- DOI: 10.1016/j.polymer.2008.04.028 -
N-O bond förtroende 1,0
“The laser was operated at with higher laser fluence but a smaller pulse number, shows (cid:1)fundamental 1064 nm three different wavelengths: harcm-1 1756 only a very weak peak at and no bands are detectmonic(cid:2), (cid:1)second harmonic(”
Califano 等 - 2008 - Matrix-assisted pulsed laser evaporation of poly ( DOI: 10.1117/1.2830660(cid:4) -
Acetate förtroende 1,0
“1530cm-1 to 8mg of drug), placed over the disk, and covered with a Bands between 1756 and assigned to the C=O methyl-esterified polyester mesh.”
Fernandes 等 - 2018 - Manufacture and Characterization of Mucoadhesive B DOI: 10.1155/2018/2403802 -
förtroende 0,9
“Text: 'free C=O group at 1756 cm-1'”
Mohamed 等 - 2020 - High-Molecular-Weight PLA-b-PEO-b-PLA Triblock Cop DOI: 10.3390/polym12051193 -
Carbonyl (C=O) förtroende 0,8
“Band at 1756 cm-1 assigned to C=O stretching.”
Lu 等 - 2021 - Visualization of Interand Intramolecular Interac DOI: 10.1177/00037028211010216 -
Amide förtroende 0,8
“Text: 'wavenumber cm-1-1584 cm-1 1756 (Amide I and Amide II)'”
Irfanita 等 - 2022 - Attenuated Total Reflectance-Fourier Transform Inf DOI: 10.21315/tlsr2022.33.2.7
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