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
Răspuns rapid
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.
Atribuiri posibile ale grupelor funcționale
| Grup funcțional | Fapte suport | Surse citate | Încredere maximă |
|---|---|---|---|
| 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 |
Clasamentul reflectă dovezile acumulate din literatură, nu o singură regulă autoritară. Confirmați întotdeauna în contextul mostrei dvs.
Materiale posibile
| Material | Vârfuri suport | Grupuri suprapuse | Surse citate |
|---|---|---|---|
| PVC | 945, 834, 1195 | Methoxy (OCH3), Methacrylate, Acetate | 1 |
Materialele sunt afișate numai atunci când același grup de literatură susține această bandă și cel puțin un vârf caracteristic suplimentar.
Logica spectrului
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.
Utilizare în condiții reale
Acest tip de interogare este comun în identificarea polimerilor, screeningul materialelor plastice necunoscute, depanarea QC, verificarea materialelor reciclate și revizuirea atribuirii vârfurilor bazată pe literatură.
Greșeli comune
- Tratarea unei benzi izolate ca dovadă a unui material fără a verifica cel puțin unul sau două vârfuri de susținere.
- Ignorând suprapunerea: mai multe grupuri funcționale pot contribui în apropierea aceluiași număr de undă.
- Omiterea validării atunci când aditivii, amestecurile, oxidarea sau contaminarea pot distorsiona spectrul.
Sfat de verificare
Când ambiguitatea rămâne, validați ipoteza prin DSC, GC-MS sau TGA, în special pentru amestecuri, probe degradate și polimeri umpluți.
Literatura din spatele acestor atribuiri
-
Carboxyl (COOH) încredere 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 încredere 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) încredere 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) încredere 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) încredere 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) încredere 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 încredere 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 încredere 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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