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
Mabilis na sagot
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.
Mga posibleng pagtatalaga ng functional-group
| Grupong functional | Mga sumusuportang katotohanan | Mga nasiping sanggunian | Pinakamataas na kumpiyansa |
|---|---|---|---|
| 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 |
Ang pagraranggo ay sumasalamin sa naipon na ebidensya ng literatura, hindi isang solong awtoritatibong tuntunin. Palaging kumpirmahin laban sa konteksto ng iyong sample.
Mga posibleng materyales
| Materyal | Sumusuportang mga peak | Mga overlapping na grupo | Mga nasiping sanggunian |
|---|---|---|---|
| PLLA | 921, 1182, 1109 | Alkyl C-H | 2 |
| TiO2 | 921, 1700, 1093 | Alkyl C-H | 1 |
Ang mga materyales ay ipinapakita lamang kapag ang parehong literatura pool ay sumusuporta sa banda na ito at hindi bababa sa isang karagdagang katangian na tuktok.
Logic ng spectrum
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.
Paggamit sa totoong mundo
Ang uri ng query na ito ay karaniwan sa pagtukoy ng polymer, screening ng hindi kilalang plastic, pag-troubleshoot ng QC, pag-verify ng recycled na materyal, at pagsusuri ng pagtatalaga ng peak na may suporta ng literatura.
Mga karaniwang pagkakamali
- Pagtrato sa isang nakahiwalay na banda bilang patunay ng isang materyal nang hindi sinusuri ang hindi bababa sa isa o dalawang sumusuportang peak.
- Hindi pinapansin ang overlap: maraming functional group ang maaaring mag-ambag malapit sa parehong wavenumber.
- Pag-laktaw sa pagpapatunay kapag ang mga additives, blends, oxidation, o contamination ay maaaring mag-distort ng spectrum.
Payo sa pagpapatunay
Kapag nananatili ang kalabuan, patunayan ang hypothesis gamit ang DSC, GC-MS, o TGA, lalo na para sa mga blend, degraded na sample, at filled polymers.
Literatura sa likod ng mga pagtatalagang ito
-
Silicon (Si) kumpiyansa 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 kumpiyansa 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 kumpiyansa 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 kumpiyansa 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 -
kumpiyansa 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 kumpiyansa 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 kumpiyansa 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 -
kumpiyansa 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
May spectrum ka ba na may ganitong band?
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