What absorbs at 1109 cm⁻¹ in an FTIR spectrum?
A band near 1109 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 1109 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 |
|---|---|---|---|
| Acetate | 16 | 16 | 1.0 |
| Methoxy (OCH3) | 15 | 15 | 1.0 |
| Methacrylate | 15 | 15 | 1.0 |
| C-O single bond | 15 | 15 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.9 |
| Silicon silicon | 1 | 1 | 0.9 |
| Nitrogen heterocycle | 1 | 1 | 0.8 |
| Silicon (Si) | 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 |
|---|---|---|---|
| polyurethane | 1109, 2270, 1700 | Methacrylate, Acetate, C-O single bond | 2 |
| ZnO | 1109, 1400, 3430 | Acetate, Methacrylate, C-O single bond | 1 |
| SnO2 | 1109, 2800, 1547 | Methoxy (OCH3), Methacrylate, Acetate | 1 |
| polyurethanes | 1109, 1740, 1728 | Methacrylate, Acetate | 1 |
| ZnO nanoparticles | 1109, 1219, 1726 | Methacrylate, Acetate, C-O single bond | 1 |
| diamond | 1109, 1378, 1332 | 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 1109 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
“The spectra 2 cm-1 of PEG-400 at (845 to 900) indicates the presence of O-O stretching [16], whereas the presence cm-1 cm-1 of 1109 peaks indicates symmetry C-O-C on aliphatic ether.”
Diantoro 等 - 2018 - Control of Dielectric Constant and Anti-Bacterial DOI: 10.1088/1757-899X/367/1/012012 -
Acetate confidence 1.0
“822(m)822(s)824(s)814(w)811(vw)-CHoutofplanedeformationinaromatic 2917(m)2923(m)2915(s)2919(vw)2915(w)asymmetricalC-Hstretchof-CH2group 1456(m)1462(s)1464(s)1462(w)1464(w)C-Cstretchingvibrationinaromatic 1232(m)1238(m)1236(s)1238(w)1242(w)a”
Investigation of the Thermal and Dielectric Behavior of Epoxy Nano-Hybrids by using Silane Modified Nano-ZnO DOI: 10.1007/s12633-017-9604-3 -
Amide confidence 1.0
“cm(cid:2)1 1109 The intensity of the shoulder at 1109 C-N stretching frequencies for various geometries obtained from ab-initio increased significantly (Fig.”
Titus 等 - 2006 - Nitrogen and hydrogen related infrared absorption DOI: 10.1016/j.tsf.2005.12.062 -
confidence 1.0
“The two charcm-1 S-O acteristic peaks for at 1109 and 617 (Figure 6b) also could be fitted to cadmium sulfate, which could be argued to form due to particle photooxidation.”
Wankhede 和 Haram - 2003 - Synthesis and characterization of Cd-DMSO complex DOI: 10.1021/cm020761w -
confidence 1.0
“Lanigan and cm-1 Pidsosny [41] found a peak at 1109 associated with the Cu-EDTA complex.”
Barros 等 - 2020 - A three-stage chemical cleaning of ion-exchange me DOI: 10.1016/j.desal.2020.114628 -
Ring structure confidence 1.0
“Sci.2018,19,3723 7of15 cm-1, cm-1, cm-1, absorbing peaks appear at 1109 1863 and 2985 which indicates that the main pyrolysates of the block polymers are all cyclic carbonates.”
Study on Thermal Decomposition Behaviors of Terpolymers of Carbon Dioxide, Propylene Oxide, and Cyclohexene Oxide DOI: 10.3390/ijms19123723 -
Acetate confidence 1.0
“assigned to the asymmetrical stretching of C-O-C groups and cm-1 The PU spectrum shows a strong absorption at 3331 cm-1 the C-O stretching vibrations at 1109 of the urethane arising from H-bonded N-H.”
Gabriela Echeverria 等 - 2015 - PolyurethanePoly(2-(Diethyl Amino)Ethyl Methacryl DOI: 10.1590/0104-1428.1716 -
Hydroxyl (O-H) confidence 1.0
“(O-H moisture).34 bending vibration absorption of related to carbonyl vibration, and the peaks at 1109 and 1104 The peak at approximately3350cm(cid:3)1isattributedtothe-OHgroups.23The cm(cid:3)1 C-O-C are related to vibration.”
Polyurethane/58S bioglass nanofibers: synthesis, characterization, and in vitro evaluation DOI: 10.1039/c5ra24786a
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