What absorbs at 2323 cm⁻¹ in an FTIR spectrum?
A band near 2323 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 6 cited sources
Quick answer
A band near 2323 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 | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| CuO | 2323, 453, 1000 | Methacrylate | 1 |
| rGO | 2323, 2358, 2930 | Methacrylate | 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 2323 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
-
Water (H2O) confidence 1.0
“BR exhibits three water bands at 2323, 2500 in the Batho-minus-rhodopsin difference spectrum”
Ota 等 - 2006 - Structural changes in the Schiff base region of sq DOI: 10.1021/bi051937l -
Carbon dioxide confidence 1.0
“The corre2323 and 2345 (O=C=O stretching) and cm-1 spondingbandareasandtheirassignmentsaredetailed 3400 (-OH vibrational stretch) corresponding b-glucan in Table 1.”
Pemmaraju 等 - 2016 - Modulation of Candida albicans Biofilm by Differen DOI: 10.1007/s11046-016-9992-8) -
Water (H2O) confidence 1.0
“This is also the case for strongly hydrogen-bonded (-), SrSRI SrSRI the minus spectrum, the bands at 3492 K cm-1 water molecules in BR (2323, 2292, and 2171 bands (-), (+)”
Suzuki 等 - 2008 - Structural Changes of Salinibacter Sensory Rhodops DOI: 10.1021/bi801358b -
Carbon dioxide confidence 1.0
“The band at 2323 shows the existence of CO 2.”
Abozaid 等 - 2018 - Characterization of Neodymium Doped Calcium Tungst DOI: 10.2298/SOS1804445A -
confidence 1.0
“2368.44cm-1 2323.25cm-1 that appeared at and indicate the made a significant alteration due to aggregation of GV presence of nitrogen linkage, which is present in the molecules on the surface of sorbent, which might reduce the structure of”
Akram 等 - 2021 - Kinetic and Isothermal Investigations of Cost-Effe DOI: 10.1155/2021/5549536 -
Alkene (C=C) confidence 0.9
“Explicit assignment: 'vibrations at wavenumbers 2323 ... indicating the presence of C=C'.”
High Selectivity Fuel from Efficient CO2 Conversion by Zn-Modified rGO and Amine-Functionalized CuO as a Photocatalyst DOI: 10.3390/ma16124314
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