What absorbs at 747 cm⁻¹ in an FTIR spectrum?
A band near 747 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 747 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 |
|---|---|---|---|
| Metal oxygen | 4 | 4 | 1,0 |
| Alkyl C-H | 3 | 3 | 1,0 |
| Aromatic ring | 2 | 2 | 1,0 |
| Carbonyl (C=O) | 2 | 2 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
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 |
|---|---|---|---|
| nanotube | 747, 1540, 1080 | Alkyl C-H | 1 |
| HDPE | 747, 1369, 1216 | Alkyl C-H, Aromatic ring, Carbonyl (C=O) | 1 |
| LDPE | 747, 1720, 1737 | Alkyl C-H, Carbonyl (C=O), Aromatic ring | 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 747 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
-
Carbonyl (C=O) confiance 1,0
“Therefore, the ging band appears between 850 and regions, even though only one carbonyl group is present, prob746cm-1 747cm-1 in the infrared and in Raman is band at ably due to Fermi resonance.”
Arjunan 等 - 2007 - Fourier transform infrared and Raman spectral assi DOI: 10.1016/j.saa.2006.09.044 -
Aromatic ring confiance 1,0
“The FTIR spectrum of FNTs/FU conjugated with FA/MNPs showed peaks at wavelengths of 747, 878, 623, 1000-1400, corresponding to benzene vibration of FF, CF=CH of FU, Fe-O, fluoro of FU respectively (Fig.”
Covalent diphenylalanine peptide nanotube conjugated to folic acid/magnetic nanoparticles for anti-cancer drug delivery DOI: 10.1016/j.jddst.2017.06.005 -
Metal oxygen confiance 1,0
“LLM confirmed rule peak-group candidate”
Retnoningtyas 等 - 2022 - Synthesis and Characterization of Methionine-Funct DOI: 10.33263/BRIAC125.58455859 -
Acetate confiance 1,0
“show C-H bond stretching vibrations, whereas the peak at specifies 1,747cm-1 cm-1 C=O stretch, and 1,769 depicts CH2/ 1,726cm-1 CH3 stretch in the EVA particle sample.”
Hossain 等 - 2023 - First evidence of microplastics and their characte DOI: 10.3389/fenvs.2023.1232931 -
Metal oxygen confiance 1,0
“LLM confirmed rule peak-group candidate”
Nadeem 等 - 2022 - Stability Analysis of Fe3O4-OA-MWCNT Nanocomposite DOI: 10.1155/2022/1859698 -
confiance 1,0
“An absorption peak appeared at cm-1 747 which could be assigned to Al-O bond of Al 2O 3.”
Efficient removal of 2-chlorophenol from aqueous solution using TiO2 thin films/alumina disc as photocatalyst by pulsed laser deposition DOI: 10.1007/s13201-021-01372-x -
Alkyl C-H confiance 1,0
“The peak at 747 is assigned to the to cm-1 C-H bending vibrations of the benzene [35].”
Thabede 等 - 2023 - Synthesis of lanthanum metal organic framework usi DOI: 10.15251/DJNB.2023.181.157
Avez-vous un spectre avec cette bande ?
Téléchargez votre spectre FTIR et obtenez un rapport d＇interprétation complet — attributions de pics avec citations bibliographiques, correspondances de bibliothèque et une chaîne de preuves avec évaluation de la confiance — en quelques secondes.