What absorbs at 1101 cm⁻¹ in an FTIR spectrum?
A band near 1101 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 1101 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 |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 7 | 5 | 1.0 |
| Siloxane (Si-O-Si) | 5 | 4 | 1.0 |
| Silicon (Si) | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Ring structure | 4 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Thiol | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Perchlorate | 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 |
|---|---|---|---|
| sodium alginate | 1101, 1636, 1080 | 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 1101 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
-
Siloxane (Si-O-Si) confidence 1.0
“LLM confirmed rule peak-group candidate”
Qin 等 - 2023 - Preparation and properties of silica solmelamine DOI: 10.1080/15685551.2022.2162280 -
Perchlorate confidence 1.0
“cm-1 molecules,31,32 observed at 1040 are assigned to the AN voltammetric peaks nearly from the beginning, due to the quick cm-1 while the peak at 1101 has been reported as being due to interchange of the perchlorate anions.”
Romero 等 - 2005 - In situ FTIR spectroscopy study of the break-in ph DOI: 10.1021/jp054026u -
Acetate confidence 1.0
“These peaks formed owing to the N-H stretching vibration of the primary amine (3309 cm-1), C-H stretching of the alkane groups (2925, 2852 cm-1), stretching of the C=C group (1643 cm-1), O-H bending of carboxylic (1400 cm-1), strong stretch”
Preparation and Physiochemical Characterization of Bitter Orange Oil Loaded Sodium Alginate and Casein Based Edible Films DOI: 10.3390/polym14183855 -
Ring structure confidence 1.0
“COC (oEG) C ArC asym Ar a 24 COC ring stretch CH 1101 Ar sym sym 2 25”
Blond 等 - 2018 - Grafting of Oligo(ethylene glycol)-Functionalized DOI: 10.1021/acs.langmuir.8b00464 -
Nucleic acid confidence 1.0
“Besides, the cm-1, control samples showed more pronounced bands at 1101 and 1063 corresponding to the nucleic acids and the -CO-O-C stretching band in cholesterol esters [36], respectively.”
Synchrotron-Based Fourier-Transform Infrared Micro- Spectroscopy of Cerebrospinal Fluid from Amyotrophic Lateral Sclerosis Patients Reveals a Unique Biomolecular Profile DOI: 10.3390/cells12111451 -
Aromatic ring confidence 1.0
“The morphology of nanocomposites N stretching mode for the benzenoid ring, while the band 1101cm-1 is assigned to an in-plane bending vibration was examined by a JSM-6700F scanning electron microat N=Q=N, Q=N+H=B B-N+H-B), scope (SEM) and a”
Guo 等 - 2012 - Preparation of a Novel Nanocomposite of Polyanilin DOI: 10.1155/2012/202794 -
confidence 1.0
“cm-1 In addition, the strong broad and sharp consecutive bands at 1101 and 1007 are attributed to symmetrical stretching vibrations of the Zn-O-Si and Si-O-Si bonds.”
Haniffa 等 - 2019 - Synergistic effect of (3-Aminopropyl)Trimethoxysil DOI: 10.1016/j.polymdegradstab.2018.11.009 -
confidence 1.0
“1036 1029 1022 Si-O stretching 1101 1088”
Karaca 等 - 2013 - Investigation of the Orientation of CTA(+) Ions in DOI: 10.1155/2013/274838
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