What absorbs at 1163 cm⁻¹ in an FTIR spectrum?
A band near 1163 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 1163 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 | 20 | 19 | 1.0 |
| Methacrylate | 19 | 19 | 1.0 |
| Acetate | 19 | 19 | 1.0 |
| Methoxy (OCH3) | 17 | 17 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Carbohydrate | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| Siloxane (Si-O-Si) | 3 | 3 | 1.0 |
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| S eq o | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 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 |
|---|---|---|---|
| bacterial cellulose | 1163, 1050, 1631 | Methoxy (OCH3), Methacrylate, C-O single bond | 1 |
| cellulose nanocrystals | 1163, 1110, 1640 | Acetate, Methacrylate, C-O single bond | 1 |
| oil | 1163, 1161, 1097 | Methoxy (OCH3), Methacrylate, C-O single bond | 1 |
| cellulose | 1163, 1735, 1650 | 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 1163 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
“1 shows the detection of broad absorption between 3750-3000 C-O-Casymmetricstretchvibrationincelluloseand 1163 cm(cid:2)1 ѵOH that was attributed to the stretching vibration of bonded hyhemicelluloses”
Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD) DOI: 10.1016/j.heliyon.2019.e02477 -
S eq o confidence 1.0
“The peak at 1163 cm-1 in the CNC spectrum revealed the presence of a sulphated group (SO2) cm-1”
Isolation and Characterization of Cellulose Nanocrystals from Oil Palm Mesocarp Fiber DOI: 10.3390/polym9080355 -
Acetate confidence 1.0
“The absorption band at 1163 in cellulose was attributed to C-O-C asymmetric stretching in cellulose and hemicelluloses.”
In-situ Production and Collection of Bacterial Cellulose on Jute and Flax Mats by Static Cultivation DOI: 10.1080/15440478.2020.1870638 -
Alkyl C-H confidence 1.0
“--C-H 1417 (cis) Bending, rocking W 2Stretching, bending St 1163 -C-O, -CH”
Fourier transform midinfrared spectroscopy evaluation of early stages of virgin olive oil autoxidation DOI: 10.1002/ejlt.201200317 -
Hydroxyl (O-H) confidence 1.0
“cm-1 cm-1 2965.11 ±3000 (Strong & Board) -COOH (O-H Stretching) 2965.11cm-1 ±3000cm-1 -COOH(O-HStretching) (Strong&Board) 769.73cm-1 600cm-1 to800cm-1 cm-1 cm-1 cm-1 769.73 600 to 800 (Medium) -COOH (O-H Bending) -COOH(O-HBending) (Medium)”
Validation of the Developed Zero-Order Infrared Spectrophotometry Method for Qualitative and Quantitative Analyses of Tranexamic Acid in Marketed Tablets DOI: 10.3390/molecules26226985 -
C-O single bond confidence 1.0
“Peaks at 1163, 1121, 1046 C-OH were ascribed to the stretching in glycosylated phenols.”
Characterization of the medium infrared spectra of polyphenols of red and white wines by integrating FT IR and UV–Vis spectral data DOI: 10.1016/j.lwt.2021.111604 -
Alkyl C-H confidence 1.0
“The bands at 1429 cm-1, 1163 cm-1, 1032 cm-1, and 892 cm-1 are attributed to C-H bending and C-O-C stretching of β-linked glucose subunits.”
Transformation of Oil Palm Waste-Derived Cellulose into Solid Polymer Electrolytes: Investigating the Crucial Role of Plasticizers DOI: 10.3390/polym13213685 -
Siloxane (Si-O-Si) confidence 1.0
“cm-1 shoulder peak at 1162.9 corresponding to stretching vibrations of siloxane groups cm-1 (Si-O-Si bonds), respectively [41], while the peak centered at 954.5 corresponds to the stretching vibration of silanol groups (Si-OH) in the silica”
CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst DOI: 10.3390/catal
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