What absorbs at 945 cm⁻¹ in an FTIR spectrum?
A band near 945 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 945 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.
可能性のある官能基アサイン
| 官能基 | 裏付け事実 | 引用元 | 最高信頼度 |
|---|---|---|---|
| C-O single bond | 5 | 5 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Silicon-oxygen (Si-O) | 4 | 4 | 1.0 |
| Silicon (Si) | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Silanol (Si-OH) | 3 | 3 | 1.0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1.0 |
| Silicate | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 0.9 |
ランキングは蓄積された文献証拠を反映しており、単一の権威あるルールではありません。常にサンプルのコンテキストと照合して確認してください。
Possible materials
| 素材 | 補助ピーク | Overlapping groups | 引用元 |
|---|---|---|---|
| PVC | 945, 834, 1195 | Methoxy (OCH3), 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 945 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.
これらのアサインの根拠となる文献
-
Carboxyl (COOH) 信頼度 1.0
“CdO cm-1, the band in the ester group at 1751 that of 1700 cm-1 CdO cm-1 On the other hand, the Acesulfame-K band at 945 does due to the stretch in carboxylic acids, and the band CdO cm-1 not overlap with any Aspartame band, but the low sig”
Armenta 等 - 2004 - FTIR determination of aspartame and acesulfame-k i DOI: 10.1021/jf049218l -
Fatty acid 信頼度 1.0
“peak areas between 945 and and peak heights at although various cis and trans fatty acids present in trans fatty acids oil.”
Quantification of trans fatty acid content in French fries of local food service retailers using attenuated total reflection ⠍ Fourier transform infrared spectroscopy DOI: 10.1016/j.foodchem.2010.09.078 -
Silanol (Si-OH) 信頼度 1.0
“X-raydiffractionspectraofpurePVC, 945cm-1 an absorption peak is seen which could be related nanoparticles, and 4wt% PVC-SiO2 nanocompure SiO2 to the Si-OH group (Si-Ostretching).”
Abdel-Baset 等 - 2016 - Characterization and Optical and Dielectric Proper DOI: 10.1155/2016/1707018 -
Water (H2O) 信頼度 1.0
“Furthermore, a new peak 945 cm(cid:2)1 43(cid:2) n showed humps when kept in water and further increases in 3PO at 1030 developed.”
Characterisation of the Bioactivity and the Solubility of a New Root Canal Sealer DOI: 10.1016/j.identj.2023.04.003 -
Silicon (Si) 信頼度 1.0
“however a new band appears at 945 This band can be attributed to Si-O vibration of SiO and it is proved structure21.”
Asmi 等 - 2016 - Synthesis and Characterisation of Composite based DOI: 10.1063/1.4945463 -
Silicon (Si) 信頼度 1.0
“Infrared analysis of the surface shows cm-1 a peak around 945 which is attributed to silicon hydroxide (Si-OH) bonds present on unfunctionnalized silica nanoparticles [6].”
Brassard 等 - 2012 - Fluorine Based Superhydrophobic Coatings DOI: 10.3390/app2020453 -
Silicate 信頼度 1.0
“Swedlund's group [35], the maximum IR absorbance at the lowest Si surface concentrations for H2SiO4 in FH suspension occurred at 945 cm-1, and this spectral feature has been attributed to a monomeric silicate surface species.”
Effects of Potassium Loading over Iron–Silica Interaction, Phase Evolution and Catalytic Behavior of Precipitated Iron-Based Catalysts for Fischer-Tropsch Synthesis DOI: 10.3390/catal12080916 -
Carbohydrate 信頼度 1.0
“cm-1 cm-1, cm-1, and 944.61 are typical for carbohydrates, and the bands at 1632.53 1553.51 and and 944.61 cm-1 are typical for carbohydrates, and the bands at 1632.53 cm-1, 1553.51 cm-1, and 1320.33 cm-1 cm-1 1320.33 can be assigned to ami”
Efficient Degradation of High-Molecular-Weight Hyaluronic Acid by a Combination of Ultrasound, Hydrogen Peroxide, and Copper Ion DOI: 10.3390/molecules24030617
このバンドを持つスペクトルがありますか？
FTIRスペクトルをアップロードすると、数秒で完全な解釈レポート（文献引用付きピークアサイン、ライブラリマッチ、信頼度評価付き証拠チェーン）を取得できます。