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
Snabbt svar
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.
Möjliga identifieringar av funktionella grupper
| Funktionell grupp | Stödjande fakta | Citerade källor | Högsta förtroende |
|---|---|---|---|
| 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 |
Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.
Möjliga material
| Material | Stödjande toppar | Överlappande grupper | Citerade källor |
|---|---|---|---|
| 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 |
Material visas endast när samma litteraturpool stöder detta band och minst en ytterligare karakteristisk topp.
Spektrumlogik
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.
Användning i verkligheten
Denna typ av fråga är vanlig inom polymeridentifiering, screening av okänd plast, felsökning av kvalitetskontroll, verifiering av återvunnet material och litteraturstödd toppidentifieringsgranskning.
Vanliga misstag
- Behandla ett isolerat band som bevis på ett material utan att kontrollera minst en eller två stödjande toppar.
- Ignorerar överlapp: flera funktionella grupper kan bidra nära samma vågtal.
- Hoppa över validering när tillsatser, blandningar, oxidation eller föroreningar kan förvränga spektrat.
Verifieringsråd
När oklarhet kvarstår, validera hypotesen med DSC, GC-MS eller TGA, särskilt för blandningar, nedbrutna prover och fyllda polymerer.
Litteratur bakom dessa identifieringar
-
Adsorbed carbon monoxide förtroende 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 -
förtroende 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 förtroende 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) förtroende 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) förtroende 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 -
förtroende 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 förtroende 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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