What absorbs at 2002 cm⁻¹ in an FTIR spectrum?
A band near 2002 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 6 cited sources
Quick answer
A band near 2002 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 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 |
|---|---|---|---|
| chitosan | 2002, 1650, 1655 | Methacrylate, Hydroxyl (O-H), C-O single bond | 1 |
| silver nanoparticles | 2002, 1636, 1631 | Hydroxyl (O-H), Methacrylate, C-O single bond | 1 |
| glycerol | 2002, 1585, 1630 | Methacrylate, C-O single bond, Methoxy (OCH3) | 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 2002 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
-
Water (H2O) confidence 1.0
“The IR spectrum is largely dominated by the In astrophysical ices, the main component is water (Greenberg strong band related to the OH stretching mode of water, while 2002), allowing a spectral window for AAN detection around cm-1 cm-1 νCN”
Borget 等 - 2012 - Aminoacetonitrile characterization in astrophysica DOI: 10.1051/0004-6361/201218949 -
Alkene (C=C) confidence 1.0
“It is known that all organic materials spectra cm-1 have small peaks at around 2300 - 2400 which are related to the effect of C = N, C = O and N = O double bond stretching vibration (Griffiths and Homes 2002).”
Elwan 等 - 2018 - DOI: 10.5028/jatm.v10.935 -
Acetate confidence 1.0
“48, films, and to the C-O stretch vibrations with bands between (2002)”
Fundo 等 - 2015 - The Effect of PolymerPlasticiser Ratio in Film Fo DOI: 10.1007/s11483-015-9394-3 -
confidence 1.0
“carbonate-richlithology.Duringtheir studies, the Si-O stretch2002, 2003a),its trace elements content (Friedrich et al.”
FTIR and Raman analyses of the Tagish Lake meteorite: Relationship with the aliphatic hydrocarbons observed in the Diffuse Interstellar Medium DOI: 10.1051/0004-6361:20034526 -
C c single bond confidence 1.0
“(2013), Kumar and cles and positive control (streptomycin), but the negative C-C stretching Gupta (2002) and Babu et al.”
Netala 等 - 2015 - First report of biomimetic synthesis of silver nan DOI: 10.1007/s13204-014-0374-6 -
Amide confidence 1.0
“Amide-B band Edem DO (2002) Palm oil: biochemical, physiological, nutritional, illustrated NH-stretching vibration and asymmetric CH-”
Influence of palm oil and glycerol on properties of fish skin gelatin-based films DOI: 10.1007/s13197-016-2243-7
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