What absorbs at 945 cm⁻¹ in an FTIR spectrum?
A band near 945 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 8 cited sources
Réponse rapide
A band near 945 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 |
|---|---|---|---|
| C-O single bond | 5 | 5 | 1,0 |
| Methoxy (OCH3) | 4 | 4 | 1,0 |
| Methacrylate | 4 | 4 | 1,0 |
| Acetate | 4 | 4 | 1,0 |
| Silicon-oxygen (Si-O) | 4 | 4 | 1,0 |
| Silicon (Si) | 4 | 4 | 1,0 |
| Hydroxyl (O-H) | 3 | 3 | 1,0 |
| Ring structure | 3 | 3 | 1,0 |
| Silanol (Si-OH) | 3 | 3 | 1,0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1,0 |
| Silicate | 2 | 2 | 1,0 |
| Carbohydrate | 2 | 2 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Fatty acid | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 0,9 |
Le classement reflète les preuves bibliographiques accumulées, et non une règle faisant autorité. Confirmez toujours dans le contexte de votre échantillon.
Matériaux possibles
| Matériel | Pics de support | Groupes chevauchants | Sources citées |
|---|---|---|---|
| PVC | 945, 834, 1195 | Methoxy (OCH3), Methacrylate, Acetate | 1 |
Les matériaux sont affichés uniquement lorsque le même ensemble de littérature soutient cette bande et au moins un pic caractéristique supplémentaire.
Logique du spectre
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 945 cm⁻¹ is usually not enough for material identification by itself.
Utilisation réelle
Ce type de requête est courant dans l＇identification des polymères, le criblage des plastiques inconnus, le dépannage du contrôle qualité, la vérification des matériaux recyclés et l＇examen de l＇attribution des pics appuyée par la littérature.
Erreurs courantes
- Traiter une bande isolée comme preuve d＇un matériau sans vérifier au moins un ou deux pics de support.
- Ignorer le chevauchement : plusieurs groupes fonctionnels peuvent contribuer près du même nombre d＇onde.
- Sauter la validation lorsque des additifs, des mélanges, l＇oxydation ou la contamination peuvent déformer le spectre.
Conseil de vérification
Lorsque l＇ambiguïté persiste, validez l＇hypothèse avec DSC, GC-MS ou TGA, en particulier pour les mélanges, les échantillons dégradés et les polymères chargés.
Bibliographie derrière ces attributions
-
Carboxyl (COOH) confiance 1,0
“CdO cm-1, the band in the ester group at 1751 that of 1700 cm-1 CdO cm-1 On the other hand, the Acesulfame-K band at 945 does due to the stretch in carboxylic acids, and the band CdO cm-1 not overlap with any Aspartame band, but the low sig”
Armenta 等 - 2004 - FTIR determination of aspartame and acesulfame-k i DOI: 10.1021/jf049218l -
Fatty acid confiance 1,0
“peak areas between 945 and and peak heights at although various cis and trans fatty acids present in trans fatty acids oil.”
Quantification of trans fatty acid content in French fries of local food service retailers using attenuated total reflection ⠍ Fourier transform infrared spectroscopy DOI: 10.1016/j.foodchem.2010.09.078 -
Silanol (Si-OH) confiance 1,0
“X-raydiffractionspectraofpurePVC, 945cm-1 an absorption peak is seen which could be related nanoparticles, and 4wt% PVC-SiO2 nanocompure SiO2 to the Si-OH group (Si-Ostretching).”
Abdel-Baset 等 - 2016 - Characterization and Optical and Dielectric Proper DOI: 10.1155/2016/1707018 -
Water (H2O) confiance 1,0
“Furthermore, a new peak 945 cm(cid:2)1 43(cid:2) n showed humps when kept in water and further increases in 3PO at 1030 developed.”
Characterisation of the Bioactivity and the Solubility of a New Root Canal Sealer DOI: 10.1016/j.identj.2023.04.003 -
Silicon (Si) confiance 1,0
“however a new band appears at 945 This band can be attributed to Si-O vibration of SiO and it is proved structure21.”
Asmi 等 - 2016 - Synthesis and Characterisation of Composite based DOI: 10.1063/1.4945463 -
Silicon (Si) confiance 1,0
“Infrared analysis of the surface shows cm-1 a peak around 945 which is attributed to silicon hydroxide (Si-OH) bonds present on unfunctionnalized silica nanoparticles [6].”
Brassard 等 - 2012 - Fluorine Based Superhydrophobic Coatings DOI: 10.3390/app2020453 -
Silicate confiance 1,0
“Swedlund's group [35], the maximum IR absorbance at the lowest Si surface concentrations for H2SiO4 in FH suspension occurred at 945 cm-1, and this spectral feature has been attributed to a monomeric silicate surface species.”
Effects of Potassium Loading over Iron–Silica Interaction, Phase Evolution and Catalytic Behavior of Precipitated Iron-Based Catalysts for Fischer-Tropsch Synthesis DOI: 10.3390/catal12080916 -
Carbohydrate confiance 1,0
“cm-1 cm-1, cm-1, and 944.61 are typical for carbohydrates, and the bands at 1632.53 1553.51 and and 944.61 cm-1 are typical for carbohydrates, and the bands at 1632.53 cm-1, 1553.51 cm-1, and 1320.33 cm-1 cm-1 1320.33 can be assigned to ami”
Efficient Degradation of High-Molecular-Weight Hyaluronic Acid by a Combination of Ultrasound, Hydrogen Peroxide, and Copper Ion DOI: 10.3390/molecules24030617
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