What absorbs at 449 cm⁻¹ in an FTIR spectrum?
A band near 449 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 449 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 | 4 | 4 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Amino acid | 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 |
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 449 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
-
confidence 1.0
“The two strong peaks 449 and 552 corresponds to O-Fe-O bending vibrations and Fe-O stretching vibrations, present in the octahedral FeO group which is 6 consistent with that reported by Liu et al [42].”
Investigation of Structural, Optical, Dielectric and Magnetic studies of Mn substituted BiFeO3 Multiferroics DOI: 10.1016/j.ceramint.2017.07.088 -
confidence 1.0
“1500 tional mode at 1609 Both the frequency and the 448 420 reveal the loss of aromatic character at the benzenoid positive character of this clear-cut band agree with the 449 421 rings and their transformation into quinoid centers as disap”
Benyoucef 等 - 2005 - Synthesis and in situ MRS characterization of cond DOI: 10.1016/j.eurpolymj.2004.10.047 -
confidence 1.0
“Therefore, infrared spectra in the region of 4000-2750 showed 448 cm-1 diclofenac bands at 3388 and 2357 assigned to free and bound N-H stretching, 449 (N-H....O) respectively, the latter through intramolecular hydrogen bonds (Kovala-Demert”
Franca 等 - 2020 - Monitoring diclofenac adsorption by organophilic a DOI: 10.1016/j.envpol.2013.04.012 -
Hydroxyl (O-H) confidence 1.0
“Fritsch et al.: OH stretching vibrations in serpentines 449”
Fritsch 等 - 2021 - Structural, textural, and chemical controls on the DOI: 10.5194/ejm-33-447-2021 -
Metal oxygen confidence 1.0
“The absorption band at 449 cm-1 proves that Zn-O was formed sucsponds to the C-N stretch of amino acids [34].”
Minhas 等 - 2023 - Green Synthesis of Zinc Oxide Nanoparticles Using DOI: 10.3390/catal13030549 -
Metal oxygen confidence 1.0
“3399 and 3615 Al-O bonds had a symmetric vibration peak cm-1, at 449, 517, and 1080 while Si-O bonds showed symmetric Figure 6.”
Sola 和 Ozyazgan - 2019 - Analyses of cement mortars containing reclaimed as DOI: 10.14256/JCE.1607.2016 -
confidence 0.95
“Explicit: 'Bands at 537 and 449 cm-1 were also observed and are attributed to the tetrahedral sites'”
da Silva 等 - 2020 - From Disposal to Reuse Production of Sustainable DOI: 10.3390/su122310159 -
Metal oxygen confidence 0.7
“Text: 'A large descending spectrum is related to Zn-O' near peak 449 cm-1.”
Facile fabrication of Zn/Zn5(OH)8Cl2·H2O flower-like nanostructure on the surface of Zn coated with poly (N-methyl pyrrole) DOI: 10.1016/j.apsusc.2011.07.046
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