What absorbs at 2946 cm⁻¹ in an FTIR spectrum?
A band near 2946 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 6 | 6 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 0 | 1.0 |
| Ketone | 1 | 0 | 1.0 |
| Ester | 1 | 0 | 1.0 |
| Carboxyl (COOH) | 1 | 0 | 1.0 |
| Carbonyl (C=O) | 1 | 0 | 1.0 |
| Amide | 1 | 0 | 1.0 |
| Acetate | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“This disappearance of the cm-1 cm-1 N-CH2 vibration bands at 2946 and 2811 indicated proton transfer between the N-CH2 (basic) of ARP and carboxylic groups (acidic) of SA.”
Multicomponent crystalline solid forms of aripiprazole produced via hot melt extrusion techniques: An exploratory study DOI: 10.1016/j.jddst.2021.102529. -
Alkyl C-H confidence 1.0
“Protein 1662 cm-1 Stretching C-H Lipids 2946 Figure 3.”
Salivary ATR-FTIR Spectroscopy Coupled with Support Vector Machine Classification for Screening of Type 2 Diabetes Mellitus DOI: 10.3390/diagnostics13081396 -
Alkyl C-H confidence 1.0
“CH asymmetric stretching”
Kavanaugh 等 - 2016 - Human mesenchymal stem cell behavior on segmented DOI: 10.1007/s10856-015-5654-5. -
Hydroxyl (O-H) confidence 1.0
“Researchers reported that cm-1 cm-1 -OH stretch, 2945.51 and 2834.66 for C-H using the fungal strain decolorization of dyes with the cm-1 stretching of alkyl benzene, 1460.07 for -C-H wavelength range 250-700 nm could be degraded to cm-1 be”
Kiran 等 - 2019 - Lignin Degrading System of Phanerochaete chrysospo DOI: 10.15244/pjoes/89575 -
Alkyl C-H confidence 0.9
“C-H stretching in alkane”
Characterization of plastic degrading bacteria isolated from sewage wastewater DOI: 10.1016/j.sjbs.2023.103628 -
Alkyl C-H confidence 0.8
“Described as typical PU peaks”
Wang 等 - 2014 - Electrospun polyurethane-core and gelatin-shell co DOI: 10.1088/1758-5082/6/1/015002.
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