What absorbs at 846 cm⁻¹ in an FTIR spectrum?
A band near 846 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 846 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 | 3 | 3 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Sulfonyl | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.5 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 846 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
“Polymers2023,15,2477 8of15 idation system, identified axial flexion and bending of the oxirane ring at 870 cm-1 and 846 cm-1 related to this group's polarization.”
Montenegro 等 - 2023 - Enzymatic and Synthetic Routes of Castor Oil Epoxi DOI: 10.3390/polym15112477 -
Alkyl C-H confidence 1.0
“The result in cm-1 peaks of the FTIR bands at 846, 1050, 2361 or 1478 figure 3(b) indicates that La and O elements are of an approxiC≡N are assigned to CH 2, C-O, stretching vibration, and CH mate molar ratio of 1:3 (H cannot be detected by”
Mu 等 - 2009 - Synthesis, characterization and photoluminescence DOI: 10.1088/0957-4484/20/34/345602 -
Carbohydrate confidence 1.0
“This likely due to dense 803cm(cid:1)1 tion bands at 846 and in Cell-PTA are attributed to and non-porous nature of regenerated cellulose membrane [21].”
Fabrication and characterization of modified microcrystalline cellulose membrane as proton exchange membrane for direct methanol fuel cell DOI: 10.1016/j.matpr.2021.01.431 -
Metal oxygen confidence 1.0
“in [BiO 6] A band centered at around 846 of the particles was slightly turned over from flakecm-1 stands for the Bi-O-Bi bond bending vibration.”
Sun 等 - 2018 - Structure and Electric Conductivity of Ce-doped Bi DOI: 10.1007/s11595-018-1934-5 -
Phosphate (PO4) confidence 1.0
“The band at 846 symbolizes trations (5% and 10% of the inhibitory concentration) and asymmetric vibrations of P-O group and stretching vibra-”
Comparison of the Effects of Statins on A549 Nonsmall‐Cell Lung Cancer Cell Line Lipids Using Fourier Transform Infrared Spectroscopy: Rosuvastatin Stands Out DOI: 10.1002/lipd.12296 -
Metal oxygen confidence 1.0
“the out-of-plane by change of the Bi-O-Bi-O-Bi to Bi-O-Al-O-Bi arrangement in Bi 2O 2CO 3, which changed the bending v2, which notes at 846 cm-1;”
Synthesis and Characterization of a New Aluminum-Doped Bismuth Subcarbonate DOI: 10.3390/cryst9090466 -
Sulfate (SO4) confidence 1.0
“/ Food Hydrocolloids 29 (2012) cm(cid:4)1 Instron Corporation) using ASTM Standard Method D 882-91 attributed to the 3,6-anhydrogalactose group, a peak at 846 cm(cid:4)1 (Pereiraetal.,2010).Filmspecimens(45(cid:5)20mm2strips)werecut corresp”
Martins 等 - 2012 - Synergistic effects between kappa-carrageenan and DOI: 10.1016/j.foodhyd.2012.03.004 -
Acetate confidence 1.0
“The bands at 1148, 1077, 1013 and 1019 cm-1 were produced by C-O stretching, while the peaks at 846 and 760 cm-1 were assigned to C-H bending and ring puckering [52].”
Zhang 等 - 2020 - Fabrication of Spray-Dried Microcapsules Containin DOI: 10.3390/foods9091316
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