What absorbs at 2966 cm⁻¹ in an FTIR spectrum?
A band near 2966 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 2966 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 | 10 | 10 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Silicon carbon | 2 | 2 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Methyl | 1 | 0 | 0.9 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
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 2966 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
-
C c single bond confidence 1.0
“C C H shows a wavenumber shift of cm for the largest 2 8 Fourier transform spectroscopy -6.5 -1 -1 -1 central peak at 2965.5 cm and cm for the second largest peak at 2955 cm .”
Absorption cross sections of 13C ethane and propane isotopologues in the 3µm region DOI: 10.1016/j.jqsrt.2017.05.012 -
Alkyl C-H confidence 1.0
“Allocation conso that the rate of degradation depends in first approach of the ("-N-CH2hardener") centration in the utmost reactive sites given in 3000-3100 C-H stretching -CH3 methyl symmetric stretching 2966 (peak) Isopropyl Table 2 (NB:”
Experimental and theoretical insights on the thermal oxidation of epoxy-amine networks DOI: 10.1016/j.polymdegradstab.2022.110188 -
Hydroxyl (O-H) confidence 1.0
“The peak at 45.02° and 74.8° matched the reflection from 3 Scientific Reports https://doi.org/10.1038/s41598-021-87363-z 3 | (2021) 11:7790 | Vol.:(0123456789) www.nature.com/scientificreports/ (cm-1) Wave number Vibration type Assignment 3”
Unveiling the role of novel biogenic functionalized CuFe hybrid nanocomposites in boosting anticancer, antimicrobial and biosorption activities DOI: 10.1038/s41598-021-87363-z -
Alkyl C-H confidence 1.0
“doi: 10.1016/j.pss.2015.11.019 cm-1 peak is visible at 3014 at both temperatures, but at 500 °C there are also absorption peaks at cm-1, cm-1 cm-1, 2933 and a double peak about 2875 arising from the C-H stretching modes of 2966 aliphatic hy”
Gordon 和 Sephton - 2016 - Rapid habitability assessment of Mars samples by p DOI: 10.1016/j.pss.2015.11.019 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Kamarudin 等 - 2018 - Adsorption of Copper Ion using Acrylic Acid-g-Poly DOI: 10.1088/1755-1315/140/1/012022 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Analysis of Chemical Structure and Antibiofilm Properties of Exopolysaccharides from Lactiplantibacillus plantarum EIR/IF-1 Postbiotics DOI: 10.3390/microorganisms10112200 -
Alkyl C-H confidence 1.0
“The peak at 2966 is cm-1 assigned to asymmetrical C-H stretching CH and peak at 2865 is assigned to 3 aldehyde C-H stretching [26].”
Muralishwara 等 - 2022 - Moisture absorption and spectroscopic studies of e DOI: 10.1007/s00289-022-04200-7 -
Hydroxyl (O-H) confidence 1.0
“The formed AgNPs (NH symmetric stretching), the FTIR peaks at 3524 cm-1 cm-1 were confirmed by using spectrophotometry and it showed (CH stretching), 2877 (OH stretching), 2966”
Viswanathan 等 - 2016 - Bactericidal paper trays doped with silver nanopar DOI: 10.1007/s12034-016-1202-2
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