What absorbs at 1155 cm⁻¹ in an FTIR spectrum?
A band near 1155 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 1155 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 | 40 | 40 | 1.0 |
| Methoxy (OCH3) | 35 | 35 | 1.0 |
| Methacrylate | 35 | 35 | 1.0 |
| Acetate | 35 | 35 | 1.0 |
| Carbohydrate | 9 | 8 | 1.0 |
| Alkyl C-H | 8 | 7 | 1.0 |
| Hydroxyl (O-H) | 6 | 6 | 1.0 |
| Phosphate (PO4) | 5 | 5 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Ring structure | 4 | 4 | 1.0 |
| C c single bond | 4 | 4 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Amino acid | 2 | 2 | 1.0 |
| Phosphorus | 2 | 2 | 1.0 |
| Nucleic acid | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 0.7 |
| Hydrogen bond | 1 | 0 | 1.0 |
| Nitrate | 1 | 0 | 0.7 |
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 |
|---|---|---|---|
| chitosan | 1155, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 2 |
| Hemicellulose | 1155, 1730, 897 | Methacrylate, Acetate, C-O single bond | 1 |
| silver nanoparticles | 1155, 1636, 1631 | Methacrylate, Acetate, 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 1155 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
“10 cm-1 The vibration ~1155 is assigned to C-O stretching mode and could originate from glycogen [38].”
Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan DOI: 10.1016/j.vibspec.2019.04.005 -
Acetate confidence 1.0
“Experiment has proven that the C-O structure (IR peak at cm-1) 1155 is in relation to the sugar ring molecules of CD.”
Studies and comparison of the liquid adsorption and surface properties of α-, β- and γ-cyclodextrins by FTIR and capillary rise method DOI: 10.1016/j.colsurfa.2012.07.003 -
Amide confidence 1.0
“moreover, the absorption band at 1381 corresponds to the cm(cid:0) COC-- 1 viscous to facilitate the formation of small droplets in the shearing amide II, and the peak at 1155 corresponds to the process, resulting in dispersion of that phas”
A composite chitosan derivative nanoparticle to stabilize a W1/O/W2 emulsion: Preparation and characterization DOI: 10.1016/j.carbpol.2020.117533 -
Acetate confidence 1.0
“The emergence of peak at 1155.36 strong intensity denotes the C-O-C asymmetric stretching in cellulose compound.”
Ikramullah 等 - 2018 - Hemicellulose and lignin removal on typha fiber by DOI: 10.1088/1757-899X/352/1/012019 -
Aromatic ring confidence 1.0
“santalinus only at 1594 cm-1, 1205 cm-1, 1155 cm-1 and 836 cm-1, corresponding to the stretching vibration of carbon atoms in the aromatic framework, C-O-C stretching vibration in extractives, C-O-”
Jin 等 - 2022 - Rapid Identification for the Pterocarpus Bracelet DOI: 10.3390/molecules27154793 -
Acetate confidence 1.0
“cm-1 (CH symmetric stretch), 1666 (C=O stretching vibration), 1438 (C-N stretching vibration), 3 cm-1 cm-1 cm-1 1363 (CH bending vibration), 1155 (C-O-C bending vibration), and 1073 (C-OH 3”
Synthesis, Characterization, and Antibacterial Activity of Cross-Linked Chitosan-Glutaraldehyde DOI: 10.3390/md11051534 -
Carbonate confidence 1.0
“The carbonate stretching appeared at 1155 Fe(OH) 10(cid:2) cm(cid:1)1.”
Synthesis and characterizations of nanosized iron(II) hydroxide and iron(II) hydroxide/poly(vinyl alcohol) nanocomposite DOI: 10.1002/app.32296 -
Acetate confidence 1.0
“1371 (m) C-O =C-H C-O C-H stretch bend, alkenes stretch rock, alkanes 1155 (s)”
Siraj 等 - 2020 - Biosynthesized silver nanoparticles from shoot and DOI: 10.2306/scienceasia1513-1874.2020.097
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