What absorbs at 2948 cm⁻¹ in an FTIR spectrum?
A band near 2948 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 5 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 5 | 5 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 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
“The two cm-1 bands at 2991 and 2948 can be attributed to the C-H bond stretching vibrations of the -CH and 3 bands at 2991 and 2948 cm-1 can be attributed to the C-H bond stretching vibrations of the -CH3 and -CH 2groups, respectively.”
Awad 等 - 2020 - Experimental Investigation of Methyl Methacrylate DOI: 10.3390/ma13245793 -
Alkyl C-H confidence 1.0
“cm-1, At 2948 one can see stretches on the main aliphatic chain of the alkanes and alkyl groups (C-H) with moderately strong absorption intensities, which show no change in the function of the cm-1 number of cryogelification cycles.”
Coria-Hernandez 等 - 2018 - Thermal, Structural, and Rheological Characterizat DOI: 10.3390/polym10040359 -
Alkyl C-H confidence 1.0
“2, the broad peak near 3396 was the stretching vibration peak of the cm-1 N-H group participating in the hydrogen-bonding carbamate, while the peak at 2948 was the methylene stretching vibration.”
Jin 等 - 2021 - Preparation of Microspheres and Microfiber Membran DOI: 10.1002/app.39967 -
confidence 1.0
“Amide A: peptide, protein N-H stretching 3053 Amide B: peptide, protein N-H stretching 2948”
Metabolic Profile Characterization of Different Thyroid Nodules Using FTIR Spectroscopy: A Review DOI: 10.3390/metabo12010053 -
Alkyl C-H confidence 1.0
“C-Hstretching cm-1, cm-1, at 2948 and 2897 C-H deformation of secondary alcohol at 1333 and 1239 C-O stretching cm-1, cm-1”
Zhuang 等 - 2020 - Observation of Potential Contaminants in Processed DOI: 10.3390/app10124345
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