What absorbs at 1111 cm⁻¹ in an FTIR spectrum?
A band near 1111 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 1111 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 | 9 | 7 | 1.0 |
| Methoxy (OCH3) | 7 | 7 | 1.0 |
| Methacrylate | 7 | 7 | 1.0 |
| Acetate | 7 | 7 | 1.0 |
| Hydroxyl (O-H) | 6 | 6 | 1.0 |
| Silicon-oxygen (Si-O) | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 0.8 |
| Carbohydrate | 1 | 1 | 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 |
|---|---|---|---|
| PVA | 1111, 1660, 2930 | Acetate, Methacrylate, C-O single bond | 1 |
| cellulose | 1111, 1735, 1650 | Acetate, Methacrylate, C-O single bond | 1 |
| lignin | 1111, 1035, 1510 | Methacrylate, Acetate, C-O single bond | 1 |
| hemicellulose | 1111, 1730, 897 | Methacrylate, Acetate, C-O single bond | 1 |
| PEG | 1111, 1650, 1342 | 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 1111 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
-
Ring structure confidence 1.0
“cm(cid:1)1, cm(cid:1)1 Figure 4 shows gradual shifts of cellulose Similarly, the bands at 1111 assigned as ring cm(cid:1)1 plane21-23 and 1059 assigned as structures from Cell-I to Cell-II by observing the stretching in cm(cid:1)1”
Characterization of chemically modified wood fibers using FTIR spectroscopy for biocomposites DOI: 10.1002/app.31746 -
Nitrogen heterocycle confidence 1.0
“This downshift value was the same as cm-1 Metal complexes with histidine ligands have been reported those of the 1111/1102 and 1094 bands observed in Fe2+/Fe3+ cm-1 to exhibit characteristic FTIR signals of the imidazole ring the spectrum o”
Noguchi 等 - 1999 - Structure of a histidine ligand in the photosynthe DOI: 10.1021/bi990631 -
confidence 1.0
“cm-1 1607 mode of water and the peak at 1111 is the longitudinal Si-O 3446 3630 1633 mode.”
Tabak 等 - 2011 - Structural analysis of naproxen-intercalated bento DOI: 10.1016/j.cej.2011.09.027 -
Acetate confidence 1.0
“a band at 1717 due to C=O stretching vibration (amide I), and a band at cm-1 C-O 1111 associated with stretching.”
Effect of PEG grafting density on surface properties of polyurethane substrata and the viability of osteoblast and fibroblast cells DOI: 10.1007/s10856-022-06668-1 -
Fatty acid confidence 1.0
“Esters [50] 1097cm(cid:1)1) ACH ACH bending and deformation vibrations (1111 and Fatty acids CAO 1065-1068 stretching - [50,51]”
Christou 等 - 2018 - Use of FTIR spectroscopy and chemometrics for the DOI: 10.1016/j.jare.2017.12.001 -
Acetate confidence 1.0
“as ν(C-O-C) 1240 C-H bending in CH-Cl and of ester 1144 C-O stretching 1111 C-O stretching”
Evaluation of the Impacts of Four Weathering Methods on Two Acrylic Paints: Showcasing Distinctions and Particularities DOI: 10.3390/coatings9020121 -
Phosphate (PO4) confidence 1.0
“However, the absence of the 1111 peak (P-O of MDP) from the PV5 spectrum is a characteristic finding.”
Dimitriadi 等 - 2021 - Degree of Conversion and Mechanical Properties of DOI: 10.3390/app -
Acetate confidence 1.0
“cm-1 FTIR data of pure PL is characterized by principal absorption peaks at 2889 (C-H stretching cm-1 cm-1 (O-H bend) and 1111 (C-O-C stretching vibrations) [5].”
Solid-state characterization of triamcinolone acetonide nanosuspensiones by X-ray spectroscopy, ATR Fourier transforms infrared spectroscopy and differential scanning calorimetry analysis DOI: 10.1016/j.ijpharm.2017.03.082
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