What absorbs at 2650 cm⁻¹ in an FTIR spectrum?
A band near 2650 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 5 cited sources
Réponse rapide
A band near 2650 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) | 3 | 3 | 1,0 |
| Carbonyl (C=O) | 2 | 2 | 1,0 |
| Hydrogen bond | 1 | 1 | 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.
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 2650 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
-
Carbonyl (C=O) confiance 1,0
“[34,35], band at 2650 and carbonyl band centred at 1693 This spectroscopic result, combined with microscopic”
Ferrant 等 - 2022 - An innovative multi-analytical strategy to assess DOI: 10.1016/j.culher.2022.04.007 -
Acetate confiance 1,0
“~2650 cm-1 γ-lactones and anhydrides C=O stretch.”
Morsch 等 - 2017 - Investigating the Photocatalytic Degradation of Oi DOI: 10.1021/acsami.7b00638 -
Hydroxyl (O-H) confiance 1,0
“O-H indicate that these two polymers are fully cm-1 band between 2650 and 2600 amorphous in nature as there were no sharp υ O-H, represented the i.e., strong hydrogen prominent peaks.”
Sahoo 等 - 2011 - Structural Analysis of Ciprofloxacin-Carbopol Poly DOI: 10.4314/tjpr.v10i3.14 -
Hydroxyl (O-H) confiance 1,0
“thick) using sputter ion coater and examined with SEM cm-1 range of 3450 to 3400 was assigned to polymeric υ and O-H (JEOL JSM-6480LV) equipped with a backscattered electron cm-1 hydrogen bonding, the band between 2650 and 2600 detector for”
Sahoo 等 - 2011 - Qualitative analysis of controlled release ciprofl DOI: 10.4103/2231-4040.85541 -
Hydroxyl (O-H) confiance 0,5
“Broad peak, likely O-D or O-H, but not explicitly assigned.”
Tanaka 等 - 2005 - FT-IR study on behavior of surface hydroxyls under DOI: 10.13182/FST05-A917
Avez-vous un spectre avec cette bande ?
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