What absorbs at 1990 cm⁻¹ in an FTIR spectrum?
A band near 1990 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 7 cited sources
Quick answer
A band near 1990 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 |
|---|---|---|---|
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Adsorbed carbon monoxide | 1 | 1 | 1.0 |
| C#c | 1 | 1 | 0.7 |
| Amide | 1 | 0 | 1.0 |
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 |
|---|---|---|---|
| silica | 1990, 1100, 1080 | Hydroxyl (O-H), Alkyl C-H | 1 |
| glycerol | 1990, 1585, 1630 | Alkyl C-H, Hydroxyl (O-H), Carbonyl (C=O) | 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 1990 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
-
Adsorbed carbon monoxide 信頼度 1.0
“cm-1 Lower wavenumber IR bands seen between 1990 and 1920 for CoRe(N) are tentatively assigned to bridging CO's on the cobalt and terminal carbonyls on Re(0) clusters.”
Kumar 等 - 2011 - In Situ FT-IR Study on the Effect of Cobalt Precur DOI: 10.1021/jp104878e -
信頼度 1.0
“silicah 2000 and 1839 Combinational bands of Si-O-Si 1990 and 1873 2000 and 1852 1008C Wavenumbers for additional peaks observed for substrate temperatures of 75 and are indicated in italics, while ''SS'' and ''AS'' stand for symmetric and”
Leewis 等 - 2006 - Ammonia adsorption and decomposition on silica sup DOI: 10.1016/j.apsusc.2005.12.115 -
Ring structure 信頼度 1.0
“These are resulting from quadrant and semicircle et al., predominantly anti-symmetric and symmetric stretching ring stretching, respectively (Colthup 1990;”
Microprobing the molecular spatial distribution and structural architecture of feed-type sorghum seed tissue (Sorghum Bicolor L.) using the synchrotron radiation infrared microspectroscopy technique DOI: 10.1107/S0909049511023727 -
Hydroxyl (O-H) 信頼度 1.0
“band was detected in the range of 3000-3600 This (cell debris obtained after ultrasound treatment with cell-bound lipase band is related to the presence of hydroxyl groups because naturally immobilized) of axial deformation of the O-H band”
Catalytic and physical features of a naturally immobilized Yarrowia lipolytica lipase in cell debris (LipImDebri) displaying high thermostability DOI: 10.1007/s13205-020-02444-6 -
Carbonyl (C=O) 信頼度 0.9
“ν(CO) for complex 3”
Ligand effects on structural, protophilic and reductive features of stannylated dinuclear iron dithiolato complexes DOI: 10.1039/d0nj04790b -
信頼度 0.9
“Text: 'band (located at 1990 ... CO'”
Electrooxidation of glycerol on platinum nanoparticles: Deciphering how the position of each carbon affects the oxidation pathways DOI: 10.1016/j.electacta.2013.09.032 -
C#c 信頼度 0.7
“Text: 'C≡C the bond in 1-propynylbenzene. The wide overtone ... cm-1 bands between 1760 and 1990 indicate the substituted'”
Kumar 等 - 2018 - Application of High-Resolution NMR and GC-MS to St DOI: 10.1021/acsomega.8b01284
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