What absorbs at 1237 cm⁻¹ in an FTIR spectrum?
A band near 1237 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 1237 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 |
|---|---|---|---|
| C-O single bond | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Amide | 5 | 4 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Lignin | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Carbohydrate | 3 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Hydrogen bond | 2 | 1 | 1.0 |
| Nucleic acid | 2 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Sulfonate | 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 |
|---|---|---|---|
| PMMA | 1237, 1722, 1383 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| lignin | 1237, 1035, 1510 | Methacrylate, Acetate, C-O single bond | 1 |
| saliva | 1237, 1648, 1664 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| collagen | 1237, 1408, 1660 | Methacrylate, Acetate, Methoxy (OCH3) | 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 1237 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
-
C c single bond confidence 1.0
“cm-1 1500 and 1385 The peak between 1237 and 1268 is attributed to C-C-O stretching vibrations of the methyl carbonyl group.”
Prasad 和 Lal - 2023 - Spectroscopic Investigations of Optical Bandgap an DOI: 10.33263/BRIAC132.187 -
Acetate confidence 1.0
“Additionally, the band at 1237 cm-1 was attributed to the symmetric C-O-C stretching vibration [12,35].”
Preparation and Characterization of Polymer Membranes Impregnated with Carbon Nanotubes for Olive Mill Wastewater DOI: 10.3390/polym14030457 -
Nucleic acid confidence 1.0
“The PO2asymmetric stretch at 1237 which represents DNA [44], showed the highest expression in PDRm, lower in ERMi, and it was absent in PVRm (Figure 4A), suggesting possible higher cell content in PDRm.”
Andjelic 等 - 2023 - Characterization of Different Types of Epiretinal DOI: 10.3390/ijms24054834 -
Amide confidence 1.0
“(2016) 73:1247-1265 cm-1 cm-1 deformation, second amide band) as well as at 1237 and at 774 (C-N stretching, third and fourth amide band).”
Thermal and surface properties of hybrid materials obtained from epoxy-functional urethane and siloxane DOI: 10.1007/s00289-015-1545-7 -
Amide confidence 1.0
“The FTIR spectrum of almost all samples examined showed the characteristic FTIR features of biological samples: the peaks of proteins at 1656-1642 cm-1 (Amide I, C=O stretching), 1542 cm-1 (Amide II, N-H bending), and 1237 cm-1 (Amide III);”
The Role of the Preanalytical Step for Human Saliva Analysis via Vibrational Spectroscopy DOI: 10.3390/metabo13030393 -
Hydroxyl (O-H) confidence 1.0
“The absorption at 1237 was the cm-1, bending of O-H [26].”
Variety Identification of Orchids Using Fourier Transform Infrared Spectroscopy Combined with Stacked Sparse Auto-Encoder DOI: 10.3390/molecules24132506 -
Carbohydrate confidence 1.0
“cm-1 cm-1) CD-WS, the intensity of the hemicellulose bands (1726 cm-1 and 1237 cm-1) decreased in treatments CD-WS, the intensity of the hemicellulose bands (1726 and 1237 decreased in treatments with P.”
Fornito 等 - 2020 - Degradative Ability of Mushrooms Cultivated on Cor DOI: 10.3390/molecules25133020 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Investigate the role of fungal communities associated with a historical manuscript from the 17th century in biodegradation DOI: 10.1038/s41529-022-00296-4
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