What absorbs at 1130 cm⁻¹ in an FTIR spectrum?
A band near 1130 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 1130 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 | 13 | 12 | 1.0 |
| Methoxy (OCH3) | 11 | 10 | 1.0 |
| Methacrylate | 11 | 10 | 1.0 |
| Acetate | 11 | 10 | 1.0 |
| Alkyl C-H | 5 | 5 | 1.0 |
| Secondary amine | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| C c single bond | 4 | 4 | 1.0 |
| Silicon-oxygen (Si-O) | 4 | 2 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Aromatic ring | 3 | 2 | 1.0 |
| Silicon (Si) | 3 | 1 | 1.0 |
| S eq o | 2 | 2 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Carbon dioxide | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Perchlorate | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Boron nitrogen | 1 | 1 | 1.0 |
| Metal oxygen | 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 |
|---|---|---|---|
| diamond | 1130, 1378, 1332 | Methoxy (OCH3) | 1 |
| polyaniline | 1130, 1565, 1570 | Methacrylate, Acetate | 1 |
| copolymer | 1130, 2921, 1540 | Methacrylate, Acetate | 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 1130 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
-
S eq o confidence 1.0
“The bands around 1130 and 1150cm(cid:1)1 are due to the symmetric SO stretching and SO 2”
Synergistic effect of copolymers composition on the electrochemical, thermal, and electrical behavior of 5-lithiosulphoisophthalic acid doped poly(aniline-co-2-isopropylaniline): synthesis, characterization, and applications DOI: 10.1002/pat.1359 -
Acetate confidence 1.0
“It is a well resolved peak with its maximum at 1130 resulting from asymmetric stretching vibrations of a C-O-C bond system [39].”
Mechanical properties, chemical analysis and evaluation of antimicrobial response of Si-DLC coatings fabricated on AISI 316 LVM substrate by a multi-target DC-RF magnetron sputtering method for potential biomedical applications DOI: 10.1016/j.apsusc.2017.03.223 -
Aromatic ring confidence 1.0
“modes with Olefinic and aromatic structures are associated with a broad absorption band between 1130 and 1550”
De 等 - 2011 - Fourier-Transform Infrared Absorption Study of the DOI: 10.1063/1.3605921 -
confidence 1.0
“2700-3500 has absorption bands at 1130 and 1344 due to nitrogen in hydrogen-related vibration at From the IR impurities predominantly in the form of C-center (single subspectra, we notice that the hydrogen-related modes locate at”
Fang 等 - 2016 - HPHT synthesis of N-H co-doped diamond single crys DOI: 10.1016/j.jcrysgro.2015.11.042 -
Boron nitrogen confidence 1.0
“=𝜇(1282cm-1)/𝜇(2120cm-1) × 5.5 × 16.5, out h-BN additive displayed typical yellow due to the 𝜇(1130cm-1), 𝜇(1282cm-1) 𝜇(2120cm-1) involvement of nitrogen impurities, which is inevitable where and 2120cm-1, in the synthesis cell.”
B–C Bond in Diamond Single Crystal Synthesized with h-BN Additive at High Pressure and High Temperature DOI: 10.1088/0256-307X/33/2/028101 -
confidence 1.0
“Characteristic absorption for C-centers (single substitutional N atoms).”
Li 等 - 2017 - Synthesis of n-type semiconductor diamond single c DOI: 10.1088/1757-899X/274/1/012131 -
Alkyl C-H confidence 1.0
“3 of 85PVAc:15LiClO polymer-salt complex the 4 peaksat1130,1438and1726cm-1 areascribedtoC-O-Csymν(C metric stretching, C-H bending and O) stretching vibrations of pure PVAc.”
Selvasekarapandian 等 - 2006 - Laser Raman and FTIR studies on Li+ interaction in DOI: 10.1016/j.saa.2006.02.026 -
Alkyl C-H confidence 1.0
“The negative鄄going band at 1710 is the stretching vibration peak of carboxyl group of aromatic al鄄 cm-1 dehydes, and the positive鄄going band at 1130 shows the consumption peak of methyl of toluene deriva鄄 tions.”
Zhu 等 - 2013 - Direct Electro-oxidation of Toluene Derivations on DOI: 10.7503/cjcu20121107
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