What absorbs at 838 cm⁻¹ in an FTIR spectrum?
A band near 838 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 838 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 |
|---|---|---|---|
| Metal oxygen | 3 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 1 | 1.0 |
| Alkyl C-H | 2 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| N eq o | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 0 | 1.0 |
| Metal hydroxyl | 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 |
|---|---|---|---|
| TiO2 | 838, 1700, 1093 | Metal oxygen, Methacrylate, Acetate | 1 |
| polyvinylpyrrolidone | 838, 1660, 1700 | Methacrylate, Acetate | 1 |
| PVP | 838, 2983, 1648 | Methacrylate, Acetate | 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 838 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
“C-H rocking of pure 2 cm(cid:3)1 ognized as the cause for the pure PVA absorption peak at PVA is considered the reason for absorption peak at 838 cm(cid:3)1, while C-H deformation vibration has been related 1419”
Metal framework as a novel approach for the fabrication of electric double layer capacitor device with high energy density using plasticized Poly(vinyl alcohol): Ammonium thiocyanate based polymer electrolyte DOI: 10.1016/j.arabjc.2020.08.006 -
N-O bond confidence 1.0
“The independence of the IR bands on the conFe3+, cm-1 2.4 with no showed the main band at 838 and centration of dissolved O also indicates that the concentration”
Nakamura 和 Nakato - 2004 - Primary intermediates of oxygen photoevolution rea DOI: 10.1021/ja0388764CCC -
confidence 1.0
“IR vibration modes of β-Phase are 838”
Abdullah 等 - 2014 - Effect of annealing process on the phase formation DOI: 10.1063/1.4895187 -
Acetate confidence 1.0
“- 1246 Esters or ethers 1034 1053 1028 1056 1072 1059 Aromatic C-O stretching 838”
Characterization and Thermal Behavior Study of Biomass from Invasive Acacia mangium Species in Brunei Preceding Thermochemical Conversion DOI: 10.3390/su13095249 -
Amide confidence 1.0
“The band cm-1 observed at 1277 is associated with C-N stretching, cm-1, and the two distinct bands occur at 838 and cm-1 639 related to the C-C ring and C-N=O bending,”
Alibe 等 - 2019 - Effects of polyvinylpyrrolidone on structural and DOI: 10.1007/s10973-018-7874-7 -
C-S single bond confidence 1.0
“The bands appearing at ~1167, ~1125 and ~1045 are associated with the C-O-C bending vibration in the propylene oxide group [21,22], while the bands at ~916, ~838 cm-1 are the characteristic bands of the stretching vibrations of the C-S-C bo”
Jamal 等 - 2014 - Solid-State Synthesis and Photocatalytic Activity DOI: 10.3390/ma7053786 -
Metal oxygen confidence 1.0
“The signal at cm-1 838 corresponds to the stretching bonds of As-O-Fe [42], although this signal was relatively faint in crystals from the TR-MNBs system (Figure 5b).”
Morales-Mendoza 等 - 2023 - Effect of Micro-Nanobubbles on Arsenic Removal by DOI: 10.3390/jof9080857 -
C-O single bond confidence 1.0
“cm-1 In the spectrum for the residues, the new bands at ~838 and ~1229 correspond to the changes to the vibration of characteristics of the ether groups as a result of C-O-C forming a”
Wang 等 - 2017 - Durability study on interlaminar shear behaviour o DOI: 10.1016/j.cemconres.2003.09.020
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