What absorbs at 2079 cm⁻¹ in an FTIR spectrum?
A band near 2079 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 3 cited sources
Quick answer
A band near 2079 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 |
|---|---|---|---|
| Adsorbed carbon monoxide | 3 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Nitrile | 1 | 1 | 0.9 |
| Hydrogen bond | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative 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 2079 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
-
Adsorbed carbon monoxide confidence 1.0
“It shows that CO adsorption gives strong bands at 2119 and 2079 cm-1 attributed to CO adsorbed”
Effect of Pt cocatalyst in Pt/TiO2 studied by in situ FTIR of CO adsorption DOI: 10.1016/S1872-2067(14)60172-8 -
Carbonyl (C=O) confidence 1.0
“In the the spent Rh-UFSi catalyst sample (Figure 4), the signals of only bridging carbonyl ligands spectrum of the spent Rh-UFSi catalyst sample (Figure 4), the signals of only bridging cm-1) cm-1 (1793 disappear, and a couple of bands at 2”
Kardasheva 等 - 2023 - Hydroformylation of Alkenes over Phosphorous-Free DOI: 10.3390/catal13050818 -
Nitrile confidence 0.9
“Explicit assignment: C≡N stretching frequency at 2079 cm⁻¹”
Gerber 和 Erasmus - 2018 - Electronic effects of metal hexacyanoferrates An DOI: 10.1016/j.matchemphys.2017.09.029
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