What absorbs at 2179 cm⁻¹ in an FTIR spectrum?
A band near 2179 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 5 cited sources
Quick answer
A band near 2179 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.
Mulige funktionelle gruppetildelinger
| Funktionel gruppe | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| Methoxy (OCH3) | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| C-O single bond | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| N-O bond | 1 | 1 | 1,0 |
| Adsorbed carbon monoxide | 1 | 1 | 1,0 |
| Silicon hydride | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
Rangering afspejler akkumulerede litteraturbeviser, ikke en enkelt autoritativ regel. Bekræft altid mod din prøvekontekst.
Possible materials
| Materiale | Understøttende toppe | Overlapping groups | Citerede kilder |
|---|---|---|---|
| TiO2 | 2179, 1700, 1093 | Methacrylate, Acetate, C-O single bond | 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 2179 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.
Litteratur bag disse tildelinger
-
Carboxyl (COOH) tillid 1,0
“The former peak deuterated formic acid monomer, Williams reported two bands of trans-HCOODat2178.8cm-1 and2142.4cm-1,whichhecouldnot can be identified as + 6, which is shifted toward higher energies ν5 ν assign.69”
The Raman jet spectrum of trans-formic acid and its deuterated isotopologs: Combining theory and experiment to extend the vibrational database DOI: 10.1063/5.0039237 -
Silicon hydride tillid 1,0
“LLM confirmed rule peak-group candidate”
FTIR Measurement of the Hydrogenated Si(100) Surface: The Structure-Vibrational Interpretation by Means of Periodic DFT Calculation DOI: 10.1021/acs.jpcc.0c11176 -
Adsorbed carbon monoxide tillid 1,0
“Besides the band due to liquid-like CO centered at 2140 the spectra are dominated cm-1 by the band centered at 2179 which can be assigned to CO adsorbed on the (101) face.”
Mino 等 - 2014 - CO2 Capture by TiO2 Anatase Surfaces A Combined D DOI: 10.1021/jp507443k -
Acetate tillid 1,0
“The peak at 2179 cm-1 is attributed to the vibration of C-O Pd species were further probed by CO using in situ FTIR, and the result is displayed in adsorbed by another kind of isolated Pd2+ [10], which was first determined as Z--Pd(OH)+ by”
Zhang 等 - 2019 - Investigation of Various Pd Species in PdBEA for DOI: 10.3390/catal9030247 -
Hydroxyl (O-H) tillid 1,0
“of the cm-1 Vibration Peak position, vibration assignments Hydrogen chloride H-Cl asymmetric stretching 3150-2600 Saturated hydrocarbon C-H stretching 2935 Plasticizer (ester group) C-O-C symmetric stretching 1120 C-O-C asymmetric stretchin”
Zhao 等 - 2022 - Experimental investigation and numerical modeling DOI: 10.1007/s10973-022-11723-8
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