What absorbs at 1186 cm⁻¹ in an FTIR spectrum?
A band near 1186 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 1186 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 | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Oxygen heterocycle | 2 | 2 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Carbohydrate | 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 |
|---|---|---|---|
| Polypropylene | 1186, 1030, 1600 | Methacrylate, Acetate, Methoxy (OCH3) | 2 |
| graphene oxide | 1186, 1150, 3400 | Methacrylate, Acetate, C-O single bond | 1 |
| CS | 1186, 1645, 1720 | Methacrylate, C-O single bond, Acetate | 1 |
| CA | 1186, 1045, 1650 | Acetate, Methacrylate, C-O single bond | 1 |
| wood | 1186, 1740, 1730 | 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 1186 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
“δDAring) band of 1510 and the DA adduct (C-O-C, at an absorption band of 1186 In agreement with the spectroscopic characterization, the presence of a cross-linked network is also (G(cid:48)) (G(cid:48)(cid:48)) confirmed by rheology, namely”
Muljana 等 - 2022 - Cross-Linking of Polypropylene via the Diels-Alder DOI: 10.3390/polym14061176 -
Acetate confidence 1.0
“As for the bands at 1242 and cm-1, 1186 they refer to the stretching of C-O-C bands of epoxy, but mostly in the phenolic groups cm-1 present in the ramie fiber constituents [41].”
Pereira 等 - 2020 - Ballistic Performance of Ramie Fabric Reinforcing DOI: 10.3390/polym12112711 -
Acetate confidence 1.0
“Peak at 1186 and 1108 by Downloaded cm-1 cm-1 was of C-O stretching.”
Qureshi 等 - 2015 - Ethyl acetate Salix alba leaves extract-loaded chi DOI: 10.1080/09205063.2015.1100843 -
Hydroxyl (O-H) confidence 1.0
“the In-O stretching vibration modes are usually observed in the region of 800-300 We T cm-1 can also recognize absorption band at 1186 related to In-O-H bending vibration [34].”
Yahia 等 - 2019 - Structural, optical, morphological and electrical DOI: 10.1016/j.surfin.2018.12.012 -
Alkene (C=C) confidence 1.0
“In the FTIR spectrum of rGO-TEPA, few representative peaks were identified at 1654, In the FTIR spectrum of rGO-TEPA, few representative peaks were identified at 1654, 1561, 1443, and 1186 cm-1, which can be attributed to the C=C stretching”
Cojocaru 等 - 2022 - Electrospun Nanofibrous Membranes Based on Citric DOI: 10.3390/polym14020294 -
Lignin confidence 1.0
“the inner finger-print average (1586-1186 To determine the ratio for the lignin peak, the average of the inner fingerprint range of To determine the ratio for the lignin peak, the average of the inner fingerprint range cm-1 cm-1 spectra fro”
Analysis of the Natural Aging of Silver Fir (Abies alba Mill.) Structural Timber Using Dendrochronological, Colorimetric, Microscopic and FTIR Techniques DOI: 10.3390/f14071363 -
C c single bond confidence 1.0
“For samples treated with SMP and SMC in cm(cid:3)1 cm(cid:3)1 3(cid:3) curve (c), the peak at 1186.04 and 1037.21 (SO cm(cid:3)1 (C-C group) and 1610.80 stretching bond) suggest the”
Synthesis and characterization of comb-shaped copolymer as a filtration reducer and comparison with counterparts DOI: 10.1039/c7ra13255g -
C-O single bond confidence 0.9
“Band at 1186 attributed to symmetric stretching of C-O-C group.”
de Faria 和 Martins-Franchetti - 2010 - Biodegradation of Polypropylene (PP), Poly(3-hydro DOI: 10.1590/S0104-14282010005000024
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