What absorbs at 829 cm⁻¹ in an FTIR spectrum?
A band near 829 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 829 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 | 3 | 1.0 |
| Aromatic ring | 4 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| N-O bond | 2 | 2 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Nitrate | 1 | 0 | 1.0 |
| Carbonate | 1 | 0 | 0.6 |
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 |
|---|---|---|---|
| ZnO | 829, 1400, 3430 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 1 |
| lignin | 829, 1035, 1510 | Alkyl C-H, Methacrylate, Aromatic ring | 1 |
| ZnO nanoparticles | 829, 1219, 1726 | Alkyl C-H, Methacrylate | 1 |
| silver nanoparticles | 829, 1636, 1631 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 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 829 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
-
Alkyl C-H confidence 1.0
“1039 Isoindole stretching 829 Isoindole stretching ϑ (C-H) 749a The conjugation between the constituent compounds can be evalOut-of-plane”
Gharagozlou 和 Naghibi - 2018 - Sensitization of ZnO nanoparticles by metal-free p DOI: 10.1016/j.jlumin.2017.12.020 -
N-O bond confidence 1.0
“cm-1 The 2-NO band is located at 829 are etched and become smooth for most of the NaNO solid 3 at the RH higher than 64.6% and exhibits a shoulder at particles.”
Lu 等 - 2008 - Molecular events in deliquescence and efflorescenc DOI: 10.1063/1.2973623(cid:5) -
Aromatic ring confidence 1.0
“band at 1512.19 and 1604 In addition, the mixture to bind HCl which was produced as a bycm-1 absorption at 829.39 showed that this aromatic product in both amidation reactions.”
Rasyid 等 - 2022 - Synthesis of N-phenethyl-p-methoxycinnamamide and DOI: 10.22146/ijc.76802 -
N-O bond confidence 1.0
“Representative spectra are shown in Figure 2a in spectral At high RH the 2-NO peak is located at 829 With”
Zhang 等 - 2014 - In Situ Observation on the Dynamic Process of Evap DOI: 10.1021/jp412073c -
Amide confidence 1.0
“C-N stretching Amine 829, 776 Strong C-H bending Alkene”
Biological Activity of Biosynthesized Silver Nanoaggregates Prepared from the Aqueous Extract of Cymbopogon citratus against Candida spp. DOI: 10.3390/nano13152198 -
Acetate confidence 1.0
“The signal at 1040 was due to the C-O-C stretching in cm-1 ethers, whereas the peak at 829 was characteristic of 1,4-substituted aromatic rings [61].”
Preparation, Thermal, and Mechanical Characterization of UV-Cured Polymer Biocomposites with Lignin DOI: 10.3390/polym12051159 -
confidence 1.0
“Clearly, nitrogen was cm-1 present on the materials surface shown by the presence of peaks at 829 associated with N-H cm-1 stretching vibrations and at 1288 associated with C-N stretching vibrations leading to the conclusion that new bonds”
Kaklamani 等 - 2010 - Effect of plasma surface modification on the bioco DOI: 10.1088/1748-6041/5/5/054102 -
Aromatic ring confidence 1.0
“The presence of an aromatic pair of substituted benzene rings from bisphenol A is confirmed by a band at 829 cm-1, while bands at 1511 and 777 cm-1 represent”
Influence of Dimethacrylate Monomer on the Polymerization Efficacy of Resin-Based Dental Cements—FTIR Analysis DOI: 10.3390/polym14020247
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