What absorbs at 1900 cm⁻¹ in an FTIR spectrum?
A band near 1900 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 1900 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.
Attributions possibles de groupes fonctionnels
| Groupe fonctionnel | Faits à l＇appui | Sources citées | Confiance maximale |
|---|---|---|---|
| Adsorbed carbon monoxide | 4 | 3 | 1,0 |
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| N-O bond | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Amide | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Ester | 2 | 2 | 1,0 |
| C-O single bond | 2 | 1 | 1,0 |
| Water (H2O) | 2 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| C n single bond | 1 | 1 | 1,0 |
| Methyl | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
Le classement reflète les preuves bibliographiques accumulées, et non une règle faisant autorité. Confirmez toujours dans le contexte de votre échantillon.
Possible materials
| Matériel | Pics de support | Overlapping groups | Sources citées |
|---|---|---|---|
| biodiesel | 1900, 858, 3470 | Alkyl C-H, Carbonyl (C=O) | 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 1900 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.
Bibliographie derrière ces attributions
-
N-O bond confiance 1,0
“Taking into - account the results on CO adsorption and literature data [69-74], 1770cm(cid:2)1 Cr3+(NO) are assigned to the bands at 1900 and”
Influence of dealumination and treatments on the chromium speciation in zeolite CrBEA DOI: 10.1016/j.micromeso.2009.04.038 -
Water (H2O) confiance 1,0
“The most striking feature in the infrared cm(cid:3)1, the oxalic acid dihydrates and the perfluorocarboxylic acid monospectrum of OXAD is the rather strong absorption near 1900 OAH(cid:1)(cid:1)(cid:1)O hydrates in the regions characteristi”
Infrared spectra of hydrogen bond network in lamellar perfluorocarboxylic acid monohydrates DOI: 10.1016/j.saa.2021.119551 -
Adsorbed carbon monoxide confiance 1,0
“However, assignment to ketene cannot and Possible Photoproducts be unequivocal in this spectral region, since carbon monoxide frequencies.27 also absorbs at the same cm-1 The absorptions above 1900 are characteristic of”
Jarmelo 等 - 2008 - Matrix-Isolated Diglycolic Anhydride Vibrational DOI: 10.1021/jp805603b -
confiance 1,0
“The band at about 1900 can be assigned to three-coordinated CO on Pd(111) or bridged CO on (100) planes.”
Facile Redox Synthesis of Novel Bimetallic Crn+/Pd0 Nanoparticles Supported on SiO2 and TiO2 for Catalytic Selective Hydrogenation with Molecular Hydrogen DOI: 10.3390/catal11050583 -
Ester confiance 1,0
“coefficients.42 cm-1) and discuss the loadings or regression Citing (two points: 1900 and 1560 and the area under the Bro:43 cm-1) Kjeldahl and "…we looked at a number of commonly ester C=O stretching band (1900-1728 was calculated occurrin”
Kollar 等 - 2017 - Nuclear Magnetic Resonance (1.40 T) and Mid Infrar DOI: 10.21577/0103-5053.20170031 -
Acetate confiance 1,0
“In the region 1402-1457 bands due to in which the bands due to the formation of imines in the area carbohydrates, glycoproteins, lipids and their characteristic cm-1, between 1900 and 1600 and the bands related to the C-O-H in-plane bending”
Mura 等 - 2012 - FTIR nanobiosensors for Escherichia coli detection DOI: 10.3762/bjnano.3.55 -
Hydroxyl (O-H) confiance 1,0
“t absorption bands below 1900 The signals do match reasonably well with a mixture of h o CO-loss isomers from the parent 1-1 isomer shown in Figure 10b.”
Photodynamics of [FeFe]-Hydrogenase Model Compounds with Bidentate Heterocyclic Ligands DOI: 10.1021/acs.jpcb.9b04675. -
Adsorbed carbon monoxide confiance 1,0
“cm-1 Figure 3A shows that the absorption bands exist at 1750 - 1850 and 1900 cm-1, - 2100 which may be ascribed to bridge type and linear type of CO adsorbed on”
In situ FTIR study on the formation and adsorption of CO on alumina-supported noble metal catalysts from H2 and CO2 in the presence of water vapor at high pressures DOI: 10.1039/c2cp23590k
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