What absorbs at 2021 cm⁻¹ in an FTIR spectrum?
A band near 2021 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 2021 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.
Возможные назначения функциональных групп
| Функциональная группа | Подтверждающие факты | Цитируемые источники | Максимальная достоверность |
|---|---|---|---|
| Methacrylate | 10 | 10 | 1,0 |
| Acetate | 10 | 10 | 1,0 |
| Amide | 10 | 10 | 1,0 |
| C-O single bond | 8 | 8 | 1,0 |
| Methoxy (OCH3) | 7 | 7 | 1,0 |
| Alkyl C-H | 7 | 7 | 1,0 |
| Hydroxyl (O-H) | 6 | 6 | 1,0 |
| Carboxyl (COOH) | 5 | 5 | 1,0 |
| Carbonyl (C=O) | 5 | 5 | 1,0 |
| Secondary amine | 4 | 4 | 1,0 |
| C n single bond | 4 | 4 | 1,0 |
| Ketone | 3 | 3 | 1,0 |
| Ester | 3 | 3 | 1,0 |
| Hydrogen bond | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Metal carbon | 1 | 1 | 1,0 |
| Carbon dioxide | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Lignin | 1 | 1 | 1,0 |
| Nucleic acid | 1 | 1 | 1,0 |
| Amino acid | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| C-S single bond | 1 | 1 | 1,0 |
| Adsorbed carbon monoxide | 1 | 0 | 0,7 |
Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.
Possible materials
| Материал | Поддерживающие пики | Overlapping groups | Цитируемые источники |
|---|---|---|---|
| PVP | 2021, 2983, 1648 | Amide, 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 2021 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.
Литература, лежащая в основе этих назначений
-
Amide достоверность 1,0
“These lines overlap, forming the amide I band, Molecules 2021, 26, 1174 4 of 14”
A Preliminary Study of FTIR Spectroscopy as a Potential Non-Invasive Screening Tool for Pediatric Precursor B Lymphoblastic Leukemia DOI: 10.3390/molecules -
Hydroxyl (O-H) достоверность 1,0
“Variation of asymmetry and symmetry stretching and Media, LLC, part of Springer (NH4?) vibration of cation were investigated by deconvoluted peak of FTIR in Nature 2021 absorbance mode at O-H region and area of deconvoluted peaks in C-O reg”
Investigations of biodegradable polymer blend electrolytes based on Cornstarch: PVP: NH4Cl and its potential application in solid-state batteries DOI: 10.1007/s10854-021-05266-1 -
Hydroxyl (O-H) достоверность 1,0
“4000-2500 Single bond Hydroxyl (O-H) Stretching (2021) Amine (N-H) New Used Ordinary Fly Bottom Aldehyde (C-H) (C≡C) 2500-2000”
Physicochemical properties of absorbent hydrogel polymers in disposable baby diapers DOI: 10.1016/j.cplett.2021.138605 -
C-O single bond достоверность 1,0
“C-C-O stretch HEMA 880 C-C-O stretch Ethanol Polymers2021,13,3886”
Determination of Dental Adhesive Composition throughout Solvent Drying and Polymerization Using ATR–FTIR Spectroscopy DOI: 10.3390/polym13223886 -
C-O single bond достоверность 1,0
“Sci.2021,11,5065 11of15 vibrations, C-OH bending deformation, C-H bond stretching and C=O and C=C groups)”
Characterization of a Spirit Beverage Produced with Strawberry Tree (Arbutus unedo L.) Fruit and Aged with Oak Wood at Laboratorial Scale DOI: 10.3390/app11115065 -
достоверность 1,0
“It has generally been shown that the intensities of the peaks Molecules 2021, 26, x FOR PEER REVIEW 9 of 18 are attributed to oxygen vacancies within the nanostructures;”
Influence of the Alcoholic/Ethanolic Extract of Mangifera indica Residues on the Green Synthesis of FeO Nanoparticles and Their Application for the Remediation of Agricultural Soils DOI: 10.3390/molecules26247633 -
Alkyl C-H достоверность 1,0
“O-H stretching 1005 C-H bending 829 C-H stretching Foods2021,10,1848”
Quantification of the Geranium Essential Oil, Palmarosa Essential Oil and Phenylethyl Alcohol in Rosa damascena Essential Oil Using ATR-FTIR Spectroscopy Combined with Chemometrics DOI: 10.3390/foods10081848 -
C-S single bond достоверность 1,0
“positions and new bands at 870 (O-C-S stretching), cm-1 The evolution of most gaseous species ceased by the end and 2021 (S-C = O stretching) likely indicates the for-”
Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source precursor for antimony sulfide thin films DOI: 10.1007/s10973-021-10885-1
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