What absorbs at 921 cm⁻¹ in an FTIR spectrum?
A band near 921 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
Brzi odgovor
A band near 921 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.
Moguće dodjele funkcionalnih skupina
| Funkcionalna skupina | Potporni dokazi | Citirani izvori | Najveća pouzdanost |
|---|---|---|---|
| Alkyl C-H | 6 | 5 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Aldehyde (CHO) | 1 | 0 | 1,0 |
Rangiranje odražava akumulirane literaturne dokaze, a ne jedno autoritativno pravilo. Uvijek provjerite u kontekstu vašeg uzorka.
Mogući materijali
| Materijal | Potporni vrhovi | Preklapajuće skupine | Citirani izvori |
|---|---|---|---|
| PLLA | 921, 1182, 1109 | Alkyl C-H | 2 |
| TiO2 | 921, 1700, 1093 | Alkyl C-H | 1 |
Materijali su prikazani samo kada ista literatura podržava ovu traku i barem jedan dodatni karakteristični vrh.
Logika spektra
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 921 cm⁻¹ is usually not enough for material identification by itself.
Upotreba u stvarnom svijetu
Ova vrsta upita uobičajena je u identifikaciji polimera, probiru nepoznate plastike, rješavanju problema u kontroli kvalitete, provjeri recikliranog materijala i pregledu dodjele vrhova potkrijepljenom literaturom.
Uobičajene pogreške
- Tretiranje jedne izolirane vrpce kao dokaza materijala bez provjere barem jednog ili dva podržavajuća pika.
- Zanemarivanje preklapanja: više funkcionalnih skupina može doprinositi u blizini istog valnog broja.
- Preskakanje validacije kada aditivi, mješavine, oksidacija ili kontaminacija mogu izobličiti spektar.
Savjet za provjeru
Kada nejasnoća ostane, validirajte hipotezu pomoću DSC, GC-MS ili TGA, posebno za mješavine, degradirane uzorke i punjene polimere.
Literatura iza ovih dodjela
-
Silicon (Si) pouzdanost 1,0
“Asymmetric stretching of Si-Ois indicated by a peak at 921 [24], symmetric bending of Si-O bond in the SiO4 1 3 cm(cid:0) cm(cid:0) 1 1 units is shown by the peak at 640 [25], asymmetric bending of Si-O-Si bond is shown by the peak at 491 [”
Reddish-orange emission from sol-gel derived Sm3+-doped Sr2La8(SiO4)6O2 phosphors DOI: 10.1016/j.ijleo.2020.165935 -
Alkyl C-H pouzdanost 1,0
“Small peaks at 921 and 1045 associated with adventitious hydrocarbons.”
Wong 等 - 2015 - Synthesis and Characterization of Atomically Flat DOI: 10.1021/jacs.5b03339 -
Alkyl C-H pouzdanost 1,0
“The peak at 3,014 is due cm-1 3,213 are due to the -C=Cand =CH modes of adsorbed to CH stretching of alkenes (Mistry, 2009), the doublet at 2,9642,921cm-1 groups,whilethe2,877cm-1 acetylene, whose formation is accompanied by the complete is”
Carbon Domains on MoS2/TiO2 System via Catalytic Acetylene Oligomerization: Synthesis, Structure, and Surface Properties DOI: 10.3389/fchem.2017.00091 -
Alkyl C-H pouzdanost 1,0
“In detail, the peak at 921 corresponds to the typical bending of C-H of”
Durazzo 等 - 2018 - Qualitative Analysis of Traditional Italian Dishes DOI: 10.3390/su10114112 -
pouzdanost 1,0
“Text: 'band at 921 cm-1 is ascribed to the PLLA crystal phases'”
Nguyen Thai Cuong 等 - 2020 - On the Nanoscale Mapping of the Mechanical and Pie DOI: 10.3390/app10020652 -
Alkyl C-H pouzdanost 1,0
“cm-1 cm-1 (C=O stretching), ≈1645 (C=O stretching), ≈1329 (C-H bending), ≈1022 and cm-1 cm-1 ≈1100 (C-H carbohydrate skeleton stretching) and 921 (Wang et al., 2016).”
Development of functional pectin edible films with fillers obtained from red cabbage and beetroot DOI: 10.1111/ijfs.14886 -
C c single bond pouzdanost 1,0
“The characteristic IR band of cm-1 921 was assigned to the coupling of the C-C backbone stretching with the CH rocking 3 α(cid:48)-forms αmode, which is ascribed to the and [32,33,55].”
Temperature-Dependent Polymorphism and Phase Transformation of Friction Transferred PLLA Thin Films DOI: 10.3390/polym14235300 -
pouzdanost 0,9
“Text: 'bands at 946 and 921 correspond to stretching'.”
Silver-controlled evolution of morphological, structural, and optical properties of three-dimensional hierarchical WO3 structures synthesized from hydrothermal method DOI: 10.1016/j.jallcom.2017.11.095
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