What absorbs at 2343 cm⁻¹ in an FTIR spectrum?
A band near 2343 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 2343 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 |
|---|---|---|---|
| Carbon dioxide | 5 | 4 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Silicon hydride | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 0.8 |
| Carbonate | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
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 2343 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
-
Carbon dioxide confidence 1.0
“The two distinct bands at 2343 and 2385 cm-1, which are not found in the absorption spectra of uncoated jadeite, may be related to carbon dioxide at room temperature (Ning, 2010).”
Zhang 等 - 2013 - CHARACTERISTICS OF COATED JADEITE JADE DOI: 10.5741/GEMS.49.4.246. -
Water (H2O) confidence 1.0
“cm-1, positive bands around 1200, 1620, and 1700 which correspond to bisulfate/sulfate anions, water bending, and respectively.29,39,41 carbonyl vibration from HCOOH, The cm-1 negative band located at 2343 is attributed to the formation of”
Celorrio 等 - 2017 - Strain Effects on the Oxidation of CO and HCOOH on DOI: 10.1021/acscatal.6b03237 -
Carbon dioxide confidence 1.0
“LLM confirmed rule peak-group candidate”
Geraldes 等 - 2014 - Glycerol Electrooxidation in Alkaline Medium Using DOI: 10.5935/0103-5053.20140044 -
Carbon dioxide confidence 1.0
“LLM confirmed rule peak-group candidate”
The influence of adsorbed substances on alkaline methanol electro-oxidation DOI: 10.1016/j.electacta.2018.10.073 -
Hydroxyl (O-H) confidence 1.0
“the CO peak near 2343 Meantime, the displacement 2 including the position and intensity of the O-H/N-H stretch of NH occurs mainly from the classical-cage NH and more cm(cid:12) 1,”
Maslakci 等 - 2017 - NH3 as unique non-classical content-former within DOI: 10.1063/1.4985668 -
Silicon hydride confidence 1.0
“The opposite effect is observed with the presence of carbon or hydrogen atoms (such as Si-H bond which cm-1) vibration mode is centered at 2343 because of their lower electron-negativity than oxygen and fluorine ones and also of the appeara”
How the chemical structure of the plasma-deposited SiOx film modifies its stability and barrier properties: FTIR study DOI: 10.1016/j.porgcoat.2019.105332 -
Carbonyl (C=O) confidence 1.0
“However, these currents become (O=C=O asymmetric stretching) 2343 CO progressively more important as the concentration of 2”
da Silva 等 - 2019 - Iridium-Based Catalysts for the Ethanol Electrooxi DOI: 10.21577/0103-5053.20190072 -
Alkyl C-H confidence 0.8
“Text states 'band appears at 2370.42, 2342.75 ... reflects the presence of alkyl group'.”
Biomimetic synthesis and anticancer activity of <i>Eurycoma longifolia</i> branch extract‐mediated silver nanoparticles DOI: 10.1049/iet-nbt.2016.0181
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