What absorbs at 808 cm⁻¹ in an FTIR spectrum?
A band near 808 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
Quick answer
A band near 808 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.
Possíveis atribuições de grupos funcionais
| Grupo funcional | Fatos de suporte | Fontes citadas | Maior confiança |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 7 | 6 | 1,0 |
| Alkyl C-H | 4 | 4 | 1,0 |
| Silicon (Si) | 3 | 3 | 1,0 |
| Metal oxygen | 3 | 3 | 1,0 |
| Amide | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Aromatic ring | 2 | 2 | 1,0 |
| Nitrogen heterocycle | 2 | 2 | 1,0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1,0 |
| Methacrylate | 2 | 1 | 1,0 |
| Acetate | 2 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Carbonyl (C=O) | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 0 | 1,0 |
| C-O single bond | 1 | 0 | 1,0 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Possible materials
| Material | Picos de suporte | Overlapping groups | Fontes citadas |
|---|---|---|---|
| SiO2 | 808, 1739, 699 | Silicon-oxygen (Si-O), Alkyl C-H, Silicon (Si) | 1 |
| polypropylene | 808, 1030, 1600 | Alkyl C-H | 1 |
| magnetite | 808, 1740, 1263 | Metal oxygen, Silicon-oxygen (Si-O) | 1 |
| Polyvinyl Alcohol | 808, 1141, 1640 | Alkyl C-H | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 808 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literatura por trás destas atribuições
-
Silicon (Si) confiança 1,0
“The adsorption cm-1 cm-1 peaks at around 808 and 457 were ascribed to Si-O (symmetric stretching vibration) [41-43].”
Study of Polyvinyl Alcohol-SiO2 Nanoparticles Polymeric Membrane in Wastewater Treatment Containing Zinc Ions DOI: 10.3390/polym13111875 -
confiança 1,0
“Peak at 460 for Si-O-Si bending and at cm-1 808 for stretching of the Si-O-Si.”
Nanostructure and Property of Electrospun SiO2-Cellulose Acetate Nanofiber Composite by Electrospinning DOI: 10.1016/j.egypro.2016.12.133 -
Alkyl C-H confiança 1,0
“In the spectra of non-aged PPc and PPcr, the main cm-1, PP bands were observed at 808 cm-1, due to the angular deformation of the out-of-plane PP bands were observed at 808 due to the angular deformation of the out-of-plane cm-1 cm-1,corres”
From Waste to Potential Reuse: Mixtures of Polypropylene/Recycled Copolymer Polypropylene from Industrial Containers: Seeking Sustainable Materials DOI: 10.3390/su14116509 -
confiança 1,0
“amino bands (NH bending, 808 and 780”
Bellido-Aguilar 等 - 2019 - Effect of a fluoroalkyl-functional curing agent on DOI: 10.1016/j.surfcoat.2019.02.006 -
Water (H2O) confiança 1,0
“H-O-H bending modes of 1590 - 1650 vibration Wagging modes of 808 3 Results and discussion vibration of coordinated water v1 symmetric stretching 930 - 995 3.1 Effect of sludge type PO43vibration of units v2 symmetric bending 404 - 470 Init”
Damalerio 等 - 2019 - Phosphorus recovery from wastewater and sludge DOI: 10.1051/matecconf/201926806016 -
Silicon (Si) confiança 1,0
“3 4000 4 cm-1 The band at 808 could be attributed to the Si-O-Si”
Synthesis of core–shell structured FAU/SBA-15 composite molecular sieves and their performance in catalytic cracking of polystyrene DOI: 10.1080/14686996.2017.1396561 -
confiança 1,0
“Si-O and Be-O bond vibration is observed at wavenumber 808 cm-1.”
Fawzy - 2021 - Separation of fine beryl from quartz via magnetic DOI: 10.37190/ppmp/132329 -
Nitrogen heterocycle confiança 1,0
“The peak at 808 cm-1 is assigned to the breathing mode of the triazine units (Figcm-1 vibrations.”
Underlying Mechanisms of Reductive Amination on Pd-Catalysts: The Unique Role of Hydroxyl Group in Generating Sterically Hindered Amine DOI: 10.3390/ijms23147621
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