What absorbs at 1423 cm⁻¹ in an FTIR spectrum?
A band near 1423 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 1423 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 |
|---|---|---|---|
| Alkyl C-H | 16 | 14 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Carbohydrate | 4 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Lignin | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 1 | 1.0 |
| Alkene (C=C) | 2 | 1 | 1.0 |
| Silicate | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Nitrate | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 0.7 |
| Ring structure | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| CMC | 1423, 1196, 850 | Alkyl C-H, Carboxyl (COOH) | 2 |
| Cellulose | 1423, 1735, 1650 | Alkyl C-H, Acetate, Methacrylate | 1 |
| biochar | 1423, 1640, 1115 | Alkyl C-H, Methacrylate, Acetate | 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 1423 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
-
Alkyl C-H confidence 1.0
“The bands around cm-1 1423 and 1325 are assigned to -CH scissoring and hydroxyl group (-OH) bending vibration, 2 1061cm-1 respectively.”
Eliza 等 - 2015 - Carboxymethyl Cellulose (CMC) from Oil Palm Empty DOI: 10.1088/1742-6596/622/1/012026 -
Amide confidence 1.0
“1423 The peak corresponding to the C-N bond and then it separated into its constituent ions leading to the formation of AgX nanoparticles [28].”
Lakshmanamoorthy 和 Manivannan - 2022 - Ionic liquids assist synthesis of AgAgX (X = Cl, DOI: 10.1007/s10854-021-06774-w -
Alkyl C-H confidence 1.0
“cm(cid:1)1, C-H bending at 1635 and 1703 stretching at 1423 and cm(cid:1)1, cm(cid:1)1 C]O C-H 1428 stretching at 1081 and bending at 8/13/2023 3.0 823cm(cid:1)1 areshiedin theanti-Alzheimer's drugs-AIL complex.”
Multi-spectroscopic monitoring of molecular interactions between an amino acid-functionalized ionic liquid and potential anti-Alzheimer's drugs DOI: 10.1039/d0ra06323a -
Alkyl C-H confidence 1.0
“The absorption peak at 1423cm(cid:1)1, increasing ammonia nitrogen concentrations, the protein content assigned to H-C-H deformation vibrations, suggested was reduced in both the LB-EPS and the TB-EPS.”
Application of biochar in a CIC reactor to relieve ammonia nitrogen stress and promote microbial community during food waste treatment DOI: 10.1016/j.jclepro.2018.10.269 -
Alkyl C-H confidence 1.0
“(C-H stretching reported that the frequencies of allicin in FTIR spectra were 3083 cm-1 2), 2978 cm-1 (C-H stretching symmetric of =CH 2),1634 cm-1 (a medium asymmetric of =CH intensity band originating from stretching of terminal C=C bond”
Tasci 等 - 2016 - Determination of alliin and allicin in the plant o DOI: 10.17660/ActaHortic.2016.1143.19 -
Hydroxyl (O-H) confidence 1.0
“The band at 1423 and 1332 was assigned to O-H stretching in-plane and cm-1 C-H stretching in symmetric of CMC.”
REMOVAL OF METAL IONS FROM AQUEOUS SOLUTIONS USING CARBOXYMETHYL CELLULOSE/SODIUM STYRENE SULFONATE GELS PREPARED BY RADIATION GRAFTING DOI: 10.1016/j.carbpol.2016.09.049 -
Alkyl C-H confidence 1.0
“The peak centered at 1423 175 (CH 2-CH bending) is a characteristic property of melanin.”
Isolation and characterization of melanin from black garlic and sepia ink DOI: 10.1016/j.lwt.2018.09.033 -
Acetate confidence 1.0
“(guayacil-syringil) (1422.6 A bond valence vibration symmetric C-O-C aromatic cm-1.”
Belo 等 - 2018 - Development of a Black Liquor Electrolyzer for Lig DOI: 10.1149/08604.0003ecst
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