What absorbs at 2982 cm⁻¹ in an FTIR spectrum?
A band near 2982 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 2982 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 |
|---|---|---|---|
| Alkyl C-H | 6 | 5 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| N h | 3 | 2 | 1.0 |
| Secondary amine | 2 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 2982 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
-
Carboxyl (COOH) confidence 1.0
“LLM confirmed rule peak-group candidate”
Fatima 等 - 2021 - Extraction and Chemical Characterization of Humic DOI: 10.3390/su13168969 -
Alkyl C-H confidence 1.0
“Assigned to C-H bond of polymers”
Madadi 和 Wei - 2022 - Characterization of Calcium Silicate Hydrate Gels DOI: 10.3390/gels8020075 -
S eq o confidence 1.0
“3 1000 S=O Stretch 2982 -CH Vibrations 3 3+ 1252 CH 3-NH rocking”
Origin of Defects and Positron Annihilation in Hybrid and All-Inorganic Perovskites DOI: 10.1021/acs.chemmater.1c03540 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
S-Adenosyl-L-Methionine and Cu(II) Impact Green Plant Regeneration Efficiency DOI: 10.3390/cells11172700 -
N h confidence 1.0
“DPPC(cid:48) + K5F2 it is 2957 (30 (50 Interestingly, the FTIR spectra of DPPC(cid:48) cm-1 ◦C)/2982 cm-1 ◦C), + K5F2 reveal a band at 2982 (30 (50 which is attributed 3+ 3+) (ν to the antisymmetric stretching of NH moiety asNH of Lys amino”
Adsorption/Desorption of Cationic-Hydrophobic Peptides on Zwitterionic Lipid Bilayer Is Associated with the Possibility of Proton Transfer DOI: 10.3390/antibiotics12071216 -
Alkyl C-H confidence 1.0
“Thus, the main IR bands of the EA/MMA cm-1 cm-1 acrylic binder at 2982, 2953, and 2875 (C-H stretching), 1730 (C=O stretching),”
Pintus 等 - 2022 - Multi-Analytical Investigations of Andy Warhol's DOI: 10.3390/polym14030633 -
Hydrogen bond confidence 1.0
“IR peaks of fenofibrate in prepared co-crystals when compared to pure drug thereby indicating the presence Materials of hydrogen bonding in the co-crystals as shown in Fenofibrate was obtained as a gift sample from Alembic 2982cm-1 Table 1.”
Shete 等 - 2018 - Solid State Characterization and Tableting Studies DOI: 10.5530/ijper.52.1.8 -
Alkyl C-H confidence 1.0
“The FTIR spectrum of oleic acid was presented earlier in presented earlier in the work [2]: the characteristic peaks at 2982, 2925, and 2857 cm-1 of cm-1 the work [2]: the characteristic peaks at 2982, 2925, and 2857 of the C-H stretching t”
Zlotnikov 等 - 2023 - Smart pHand Temperature-Sensitive Micelles Based DOI: 10.3390/pharmaceutics15041135
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