What absorbs at 1157 cm⁻¹ in an FTIR spectrum?
A band near 1157 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 1157 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 | 27 | 26 | 1.0 |
| Methoxy (OCH3) | 23 | 22 | 1.0 |
| Methacrylate | 23 | 22 | 1.0 |
| Acetate | 23 | 22 | 1.0 |
| Carbohydrate | 10 | 9 | 1.0 |
| Alkyl C-H | 8 | 7 | 1.0 |
| C c single bond | 6 | 6 | 1.0 |
| Aromatic ring | 4 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 3 | 2 | 1.0 |
| Nucleic acid | 2 | 2 | 1.0 |
| Alkene (C=C) | 2 | 1 | 1.0 |
| Phosphate (PO4) | 2 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| N h | 1 | 1 | 0.9 |
| Carbonyl (C=O) | 1 | 1 | 0.9 |
| C-S single bond | 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 |
|---|---|---|---|
| hydrogel | 1157, 1632, 1062 | Methacrylate, Acetate | 1 |
| poly(vinyl alcohol) | 1157, 1700, 2993 | Acetate, Methacrylate, C-O single bond | 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 1157 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
-
Acetate confidence 1.0
“C-O C-O 1089 stretching 1157 stretching C-O C-O 987 stretching 1084 stretching Table 2 The Particle Size by XRD of Chemically Synthesized C-O”
El Bialy 等 - 2020 - Comparative Toxicological Effects of Biologically DOI: 10.2147/IJN.S241922 -
Alkyl C-H confidence 1.0
“As a result, their cm-1) (~1157cm-1) corresponding ν(C-H) stretches (~2926 and (C-H) deformations can M.contortum contribute to the intensity increase of CH in NP4 treatment for [59,60].”
Response to nutrient variation on lipid productivity in green microalgae captured using second derivative FTIR and Raman spectroscopy DOI: 10.1016/j.saa.2021.120830 -
Acetate confidence 1.0
“Furthermore, the addition of POM cm-1 into PVA-GA induces a slight increase in peak intensity at 1083 corresponds to C-O-C stretching cm-1 cm-1 vibration and new peaks at 1157 and 775 indicate the existence of -CN and -C-Cl stretching vibra”
Hendrawanh 等 - 2019 - Poly (vinyl alcohol)glutaraldehydePremna oblongi DOI: 10.1088/1757-899X/509/1/012048 -
Acetate confidence 1.0
“5 of 15 Polymers2023,15,2477 5of15 cm-1 peak characteristic of the epoxy ring, the conversion of the peak at 3009 is related cm-1 to hydroxyl stretching, which is verified at 3393 (Figure 2b), and C-O absorption cm-1), (1157 indicating modi”
Montenegro 等 - 2023 - Enzymatic and Synthetic Routes of Castor Oil Epoxi DOI: 10.3390/polym15112477 -
Carbohydrate confidence 1.0
“LLM confirmed rule peak-group candidate”
Examination of the lignin content in a softwood and a hardwood decayed by a brown-rot fungus with the acetyl bromide method and Fourier transform infrared spectroscopy DOI: 10.1002/pola.20071 -
Nucleic acid confidence 1.0
“Thus, the changes of the spectral 41 of peak intensity of the second derivative spectra at 1171 bands annotated to another left-handed double helix DNA - 42 cm-1 cm-1 cm-1 cm-1 to 1157 (I )/ I )), attributed to the ν (1171 (1157 cm-1)3 the”
Song 和 Kazarian - 2020 - Effect of Controlled Humidity and Tissue Hydration DOI: 10.1021/acs.analchem.0c01002 -
Ring structure confidence 1.0
“The presence of cyclic succinimide ring (-N- (CO-) 2) thermally cured BMIX shows bands at 1157, 1396 and cm-1 corresponds to the stretching of -C-O-C1713 structure in polyBMII.”
Surender 等 - 2014 - Bismaleimide and Bispropargyl Ether Blends Curing DOI: 10.1134/S1560090414050157 -
Carbohydrate confidence 1.0
“studies have shown extensively that both lignin and cellulose components can participate in the photooxidation reactions in wood surfaces, resulting in signifi cant increase in absorption.4,5,14 carbonyl However, in the present study the cm”
Wang 和 Ren - 2009 - Surface deterioration of moso bamboo (Phyllostachy DOI: 10.1007/s10086-008-0994-0
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