What absorbs at 810 cm⁻¹ in an FTIR spectrum?
A band near 810 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 810 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 | 10 | 10 | 1.0 |
| Silicon-oxygen (Si-O) | 10 | 7 | 1.0 |
| Silicon (Si) | 7 | 6 | 1.0 |
| Alkene (C=C) | 6 | 5 | 1.0 |
| Siloxane (Si-O-Si) | 6 | 4 | 1.0 |
| Aromatic ring | 5 | 5 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Ring structure | 5 | 4 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Nitrogen heterocycle | 4 | 3 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Aldehyde (CHO) | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Carbonate | 1 | 0 | 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 |
|---|---|---|---|
| PMMA | 810, 1722, 1383 | Alkyl C-H | 1 |
| Polysaccharide | 810, 1637, 1320 | Alkyl C-H | 1 |
| PVDF | 810, 1160, 840 | 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 810 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
-
Oxygen heterocycle confidence 1.0
“It is worth mentioning that the peak at 810 (figure 8(c)) which corresponds to 27 28 the epoxy ring in AESO structure has gradually become weaker and almost disappeared after 30”
Ataei 等 - 2020 - Electrosprayed PMMA microcapsules containing green DOI: 10.1088/1361-665X/ab9754 -
Nitrogen heterocycle confidence 1.0
“The structure of the g-C 3N can be considered as 4 4 810cm-1 peak at graphite-like single layers aligned each other along the hexagonal can be attributed to the s-triazine (C 3N 3) breathing 1326-1433cm-1 1500-1627cm-1 c-axis[18].Theweakdif”
Solvothermal synthesis of the special shape (deformable) hollow g-C3N4 nanospheres DOI: 10.1016/j.matlet.2011.01.008 -
Borate confidence 1.0
“cm-1 cm-1 B-P ∼810 B-P ∼472 vibration mode located at that band in boron phosphide is located at with a shoulder at cm-1 ∼850 B-O-B P-P along with other peaks related to while symmetrical stretching mode is located at cm-1”
Dalui 等 - 2008 - Boron phosphide films prepared by co-evaporation t DOI: 10.1016/j.tsf.2007.09.047 -
confidence 1.0
“Assigned to α-crystalline phase.”
Spectroscopic and thermal investigations of poly(vinylidene fluoride) films composites with LaNi3Co2 DOI: 10.1002/crat.200610789 -
Alkyl C-H confidence 1.0
“Spectra also showed absorption bands in the 2,990-2,810cm-1, ROP with a reasonable monomer conversion, and it is also which are related to number range of C-H suitable for the copolymerization reaction.”
Herrera-Kao 等 - 2020 - Microwave-assisted synthesis of the lipase-catalyz DOI: 10.1515/epoly-2020-0067 -
Silicon (Si) confidence 1.0
“cm-1 Confirmation of the grafting process can be seen from the new FTIR peaks at 810 cm-1 13C-NMR and 749 which are attributed to the Si-C stretching and Si-C, and new signals at 10.3, 21.7 and 42.7 ppm which are assigned to C7, C8, and C9”
Indarti 等 - 2019 - Silylation of TEMPO oxidized nanocellulose from oi DOI: 10.1016/j.ijbiomac.2019.05.161 -
confidence 1.0
“Here, the O(1s) 5 1070cm(cid:4)1, obvious peaks in SiO spectrum, 810 and and spectrum of the Ta(N,O) film reveals that the oxygen in the 2 four obvious peaks in Ta(N,O) spectra, 510, 615, 805, low nitrogen films is believed to arise from th”
Microstructure and Thermal Diffusivity Investigations of RF-Sputtered Tantalum Nitride Films DOI: 10.1143/JJAP.41.5367 -
Acetate confidence 1.0
“In addition, -1 the absorption peak at 810 cm is typical of C-O-S stretching.”
Kazachenko 等 - 2021 - Food Xanthan Polysaccharide Sulfation Process with DOI: 10.3390/foods10112571
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