What absorbs at 549 cm⁻¹ in an FTIR spectrum?
A band near 549 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 549 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 | 3 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| silver nanoparticles | 549, 1636, 1631 | Methacrylate, C-O single bond, 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 549 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
“Cthe spectra at 3keV with an atomic percentage of 55.32 indicates the presence of band at wavenumber 549 Previous studies have also reported that the nanoparticle size Br functional group belongs to alkyl halides.”
Biofabrication of silver nanoparticles from aqueous leaf extract of Leucas aspera and their anticancer activity on human cervical cancer cells DOI: 10.1088/2043-6254/ab5103 -
confidence 1.0
“Text: 'vibration bands at around 549 and 1226 indicated the presence of double 5-ring in ZSM-5.'”
Synthesis of ZSM5 Zeolite Particles Using Triethanol Amine as StructureDirecting Agent DOI: 10.1111/j.1551-2916.2011.05006.x -
Metal oxygen confidence 1.0
“Cr O , nopeakof 2oranyotherstoichiometryofchromiumoxidewasfoundinthe CrO 2 3 investigation.TheRamanbandcentredat549cm-1isofA 1gmodesymmetry,whiletheshiftat304cm-1and 350cm-1areofE gsymmetry[16,17].”
Ogwu 等 - 2016 - Corrosion, ion release and Mott-Schottky probe of DOI: 10.1088/2053-1591/3/4/045401 -
Metal oxygen confidence 1.0
“437cm(cid:2)1and 598cm(cid:2)1 absorption bands at 549, are related to the vibrations of the metal-oxygen bond in octahedral and tetrahedral sites, respectively.”
Rasouli 等 - 2020 - Structural, magnetic, and microwave absorption pro DOI: 10.1080/08327823.2020.1714104 -
Aromatic ring confidence 1.0
“1A, 1E), both the 1,649 and and cm-1, cm-1, cm-1 1,516 1,496 (aromatic ring skeleton vibracm-1 absorption peaks appear simultaneously the 1,549 cm-1, cm-1 1,375 (C-H bending vibration), and tion), 1,472 in their spectra.”
Ch'ng 等 - 2016 - Vasorelaxation Study and Tri-Step Infrared Spectro DOI: 10.3831/KPI.2016.19.016 -
Acetate confidence 1.0
“Cells were cultured in T-75 conformational changes in both proteins and nucleic acids, as 80-90% flasks (Greiner, USA) and at confluence, they were C-O well as showed a higher band of carbohydrates in A549 sub-cultured in a 1:10 to 1:12 spl”
Guler 等 - 2019 - Characterization of CD133(+)CD44(+) human prostat DOI: 10.1039/c9an00093c -
confidence 1.0
“bond between Mg and O shows a peak at 549 cm-1 Int.”
Lopez-Rodriguez 等 - 2023 - Dyeing with Hydrotalcite Hybrid Nanoclays and Disp DOI: 10.3390/ijms24010808 -
Metal oxygen confidence 0.9
“Explicit assignment in text.”
Velayutham 和 Selvapandiyan - 2019 - Effect of yttrium ion on the properties of tri eth DOI: 10.1016/j.heliyon.2019.e02091
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a confidence-rated evidence chain — in seconds.