What absorbs at 807 cm⁻¹ in an FTIR spectrum?
A band near 807 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 807 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 |
|---|---|---|---|
| Alkyl C-H | 4 | 4 | 1.0 |
| Aromatic ring | 4 | 4 | 1.0 |
| Metal oxygen | 3 | 3 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 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 |
|---|---|---|---|
| MCM-41 | 807, 2170, 1655 | Alkyl C-H | 1 |
| lignin | 807, 1035, 1510 | Alkyl C-H, Aromatic ring | 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 807 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
-
confidence 1.0
“cm(cid:50)1 solution, three peaks appear at 807 immersing in Gravimetric porosity of as-etched porous silicon films was cm(cid:50)1 (cid:126)Si-O-Si mode(cid:33), (cid:126)Si-H asymmetric stretching 886 about 70%.”
Huang 和 Zhai - 1997 - Fourier transform infrared study of porous silicon DOI: 10.1116/1.589575 -
Aromatic ring confidence 1.0
“vibrations at 2969 and 2862 respectively, and bridges -CH 2at The bands at 807 and cm-1 cm-1 755 are related to aromatic torsion vibrations [25].”
Synthesis and Characterization of Mesoporous Silica Functionalized with Calix[4]arene Derivatives DOI: 10.3390/ijms131013726 -
confidence 1.0
“TiO nanoparticles have 2 additional peaks were recorded at 1454 and 1381 cm-1, due to the asymmetric and symmetric deformation cm-1 characteristic peaks at 807 corresponding to Ti-O-Ti groups and a broad peak of Ti-OH groups”
Eleftheriadou 等 - 2020 - Development of Novel Polymer Supported Nanocomposi DOI: 10.3390/app10072368 -
Methoxy (OCH3) confidence 1.0
“corresponding to aliphatic and aromatic -OH (3415 cm-1), aromatic ring modes (1595 cm-1 and 1140 cm-1), carbonyl group (1684 cm-1), aliphatic -CH3 (2944 cm-1) and CH2 groups (1453 cm-1), symmetric -CH3 stretching of the methoxyl groups (285”
Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures DOI: 10.3390/ma14113024 -
Aromatic ring confidence 1.0
“cm-1(C=C 807cm-1 1604, 1485 aromatic bending),”
Lee 和 Kim - 2014 - Synthesis and Characterization of Thermoplastic El DOI: 10.7317/pk.2014.38.5.596 -
Metal oxygen confidence 1.0
“LLM confirmed rule peak-group candidate”
Gas phase dehydration of glycerol to acrolein over WO3-based catalysts prepared by non-hydrolytic sol–gel synthesis DOI: 10.1039/c8ra01575a -
Alkene (C=C) confidence 1.0
“resins before (red lines) and after UV-curing process (green lines), it is noticeable that the peak at 1638 cm-1, ascribed to the acrylic C=C stretching and the peaks at 983 cm-1 and at 807 cm-1, characteristic of =C-H stretching in acrylic”
Rajczak 等 - 2020 - Preparation and Characterization of UV-Curable Acr DOI: 10.3390/polym12020358 -
C c single bond confidence 1.0
“and 1,321 Several studies have shown that the and thus is due to cm-1 Figure 6 shows the FTIR spectra of VEEA and adsorption band at 807 due to C C twisting cm-1 due to C C diethylene glycol monoethyl ether acetate.”
Curing behavior of a UV‐curable inkjet ink: Distinction between surface‐cure and deep‐cure performance DOI: 10.1002/app.49218
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