What absorbs at 669 cm⁻¹ in an FTIR spectrum?
A band near 669 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 669 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 |
|---|---|---|---|
| Carbon dioxide | 5 | 5 | 1,0 |
| Adsorbed carbon monoxide | 4 | 4 | 1,0 |
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Alkyl C-H | 3 | 3 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Alkene (C=C) | 2 | 2 | 1,0 |
| Silicon (Si) | 2 | 2 | 1,0 |
| Amine primary | 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 |
| Urea | 1 | 1 | 1,0 |
| Silicon nitrogen | 1 | 1 | 1,0 |
| Silicon carbon | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 0,9 |
| Carbonate | 1 | 1 | 0,7 |
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 |
|---|---|---|---|
| PET | 669, 1408, 800 | Alkyl C-H, Carbonyl (C=O) | 1 |
| silver nanoparticles | 669, 1636, 1631 | Alkyl C-H | 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 669 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
-
Alkyl C-H încredere 1,0
“A very prominent band at 669 could Downloaded C-H be related to aromatic out-of-plane deformations, rather than to mineral matter, because its intensity decreases in the FTIR spectra of the insoluble fractions (e.g., samples”
Georgakopoulos 等 - 2003 - Study of low rank Greek coals using FTIR spectrosc DOI: 10.1080/00908310390232442 -
încredere 1,0
“The disappearance of O-H band and the appearance of a cm-1 new band at 668.56 is associated with Ag-O bond which confirms the incorporation of”
Haq 等 - 2018 - Fabrication of pure and moxifloxacin functionalize DOI: 10.1016/j.jphotobiol.2018.07.011 -
Acetate încredere 1,0
“The Mn(CO) 5X correlation indi5 458s 457s M-COstretching 669cm-1 band is an E mode involving Mn cates that the C O”
Mahmood 等 - 2006 - Comparative vapour phase FTIR spectra and vibratio DOI: 10.1016/j.saa.2005.11.024 -
Silicon (Si) încredere 1,0
“The peaks corresponding to Si-C are 611, 653, cm-1 669, 740, 834 and the peaks corresponding to Si-N are in the”
Optical and photoelectrochemical properties of nitrogen-doped a-SiC thin films deposited by reactive DOI: 10.1080/2374068X.2021.1890420 -
Alkene (C=C) încredere 1,0
“cm-1 cm-1 cm-1 aromatic), 1635 (C=C stretch, aromatic), 1514 (NH), 1016 (C-O stretch, cm-1 hydroxyl), 669 (=C-H bending, alkene) (Masum et al., 2019).”
Pathak 等 - 2020 - Attenuation of hepatic and breast cancer cells by DOI: 10.1016/j.bcab.2020.101863 -
Silicon (Si) încredere 1,0
“According to the literatures [34, 36], the cm-1 presence of weak absorption peaks at about 669 and cm-1 684 is related to the vibrations modes of Si-O band.”
Magnetron sputtering technique for analyzing the influence of RF sputtering power on microstructural surface morphology of aluminum thin films deposited on SiO2/Si substrates DOI: 10.1007/s00339-021-04892-0 -
Urea încredere 1,0
“The peaks due to the urea domain cm-1 cm-1, were characterized by bands at 1626-1645 and 1651-1669 attributed to the ordered and were characterized by bands at 1,626-1,645 cm-1 and 1,651-1,669 cm-1, attributed to the ordered and disordered”
Che 等 - 2019 - Investigations on Aging Behavior and Mechanism of DOI: 10.3390/ma12213636 -
Hydroxyl (O-H) încredere 1,0
“2 3/2 1/2 distinguish27,28, (952.2eV) are too close to we intuitively dried samples showed a characteristic O-H stretching vibration 669cm-1, Cu+ /Cu0 which was ascribed to the copper silicate ratio by Cu LMM X-ray induced Auger determined”
Converting waste PET plastics into automobile fuels and antifreeze components DOI: 10.1038/s41467-022-31078-w
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