What absorbs at 796 cm⁻¹ in an FTIR spectrum?
A band near 796 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 796 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.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 13 | 11 | 1.0 |
| Siloxane (Si-O-Si) | 6 | 6 | 1.0 |
| Silicon (Si) | 5 | 5 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Metal oxygen | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Silicon carbon | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| SiC | 796, 791, 805 | Silicon-oxygen (Si-O), Silicon (Si), Siloxane (Si-O-Si) | 1 |
| silica | 796, 1100, 1080 | Silicon-oxygen (Si-O), Silicon (Si), Siloxane (Si-O-Si) | 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 796 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.
Literature behind these assignments
-
Silicon carbon confidence 1.0
“Raman spectra showed two characteristic peaks at 796 and 968 which are corresponding to transversal h-SiC, optic mode and longitudinal optic mode of respectively.”
Baek 等 - 2006 - Structural characterization of beta-SiC nanowires DOI: 10.1016/j.msec.2005.09.083 -
Alkyl C-H confidence 1.0
“In addition, the peak at cm-1 796 was the area showing the C-H bonding of the cellulose and aniline aromatic rings.”
Burhan 等 - 2020 - Preparation of Cyperus diffusus Vahl cellulose-pol DOI: 10.1088/1757-899X/833/1/012063 -
confidence 1.0
“Besides Energy Dispersive X-Ray which validated the chemical constituent of the silica NPs, the Fourier transform infrared (FT-IR) spectra showed cm-1 cm-1 peaks at 796.4 and 1052 corresponding to O-Si-O symmetric stretching vibration and O”
Green synthesis and characterization of UKMRC-8 rice husk-derived mesoporous silica nanoparticle for agricultural application DOI: 10.1038/s41598-022-24484-z -
Alkene (C=C) confidence 1.0
“The peak of 1064.25 cm-1 and 796.10 cm-1 attributed to C=C stretching of hemicellulose and C=C stretching of vinylidene alkenes, respectively.”
Preparation and Characterization of Sound-Absorbent Based on Polystyrene Reinforced Primary Sludge and Fly Ash from Pulp Mill DOI: 10.14716/ijtech.v14i3.5131 -
Metal oxygen confidence 1.0
“The FTIR spectra provide the evidence of W-O 4]2cm-1 of stretching vibration in [WO tetrahedrons at 796 and W-O bending bands at cm-1.”
Lai 等 - 2013 - Controlled Synthesis of CaWO4 Microcrystalline via DOI: 10.1080/10584587.2013.780145 -
Silicon (Si) confidence 1.0
“Methyacryl (MM) functionalized silica demonstrates charcm-1 acteristic absorption peak at 796 assigned to -Si-OCH 3”
Nasreen 等 - 2019 - Hybrid mesoporous silicates A distinct aspect to DOI: 10.1016/j.sjbs.2015.08.014 -
Hydroxyl (O-H) confidence 1.0
“Twin peaks appeared at 796 and 899 and accounted for the metal hydroxide stretching TGA profile cm(cid:1)1 explained the bendvibration.”
Synthesis and characterizations of nanosized iron(II) hydroxide and iron(II) hydroxide/poly(vinyl alcohol) nanocomposite DOI: 10.1002/app.32296 -
confidence 1.0
“The characteristic absorption peaksarefoundtobeat2922cm-1isduetotheC Hstretching,1566cm-1iscorrespondsto cm-1 cm-1 C stretching vibration of quinoid ring, 1548 for C N bond stretching, 1494 C cm-1 is corresponds to stretching vibration of b”
Patil 等 - 2011 - Electrical Conductivity of PolyanilineNiZnO3 Comp DOI: 10.1080/00150193.2011.620836
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