What absorbs at 2963 cm⁻¹ in an FTIR spectrum?
A band near 2963 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 2963 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 | 17 | 16 | 1.0 |
| Methyl | 3 | 2 | 1.0 |
| Methoxy (OCH3) | 3 | 2 | 1.0 |
| Methacrylate | 3 | 2 | 1.0 |
| Acetate | 3 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 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 |
|---|---|---|---|
| Polyurethane | 2963, 2270, 1700 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 1 |
| collagen | 2963, 1408, 1660 | Methacrylate, Alkyl C-H, Methoxy (OCH3) | 1 |
| Fe3O4 | 2963, 2358, 1673 | Alkyl C-H, Methacrylate | 1 |
| graphite | 2963, 1640, 1326 | Alkyl C-H, Methacrylate, 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 2963 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
-
confidence 1.0
“al.6 et Lee absorption lines at 3001.8 and 3013.3 et al., ing to the assignment by Lee the matrix shift of the cm-1 ν assigned the 2962.7 line to the vibrational tran-”
Miyamoto 等 - 2012 - Cluster size resolving analysis of CH3F-(ortho-H-2 DOI: 10.1063/1.4765698 -
Alkyl C-H confidence 1.0
“detected at 2962.67 cm-1 and 756.46 cm-1 can be attributed to the C-H stretching and bending vibration, respectively.”
Cimavilla-Roman 等 - 2020 - Influence of silica aerogel particles on the foami DOI: 10.1016/j.eurpolymj.2020.109884 -
Alkyl C-H confidence 1.0
“As Fe 3O 4-g-C 3N was covered with the 4 cm-1 polymer, the weak band at 2963 probably is due to the stretching vibration of aliphatic CH in the polymer structure.”
Silver incorporated into g-C3N4/Alginate as an efficient and heterogeneous catalyst for promoting click and A3 and KA2 coupling reaction DOI: 10.1038/s41598-021-93239-z -
Hydroxyl (O-H) confidence 1.0
“The absorptions between The peaks at 2963 and 2902 are attributed cm-1 νOH νNH νCH 3100-3400 are due to the and to the stretching vibrations (asim and sim) 2”
Drobota 等 - 2019 - INVESTIGATION OF PROPERTIES OF NANOFIBERS FROM COL DOI: 10.1021/bm050086u -
Siloxane (Si-O-Si) confidence 1.0
“cm-1, peaks assigned to silicone are observed at 1008 1258 cm-1 cm-1 and 2963 and due to stretching vibrations of SiO-Si, bending vibrations of Si-CH and stretching vibra3 tions of CH 3groups, respectively.”
Ghani 等 - 2021 - Molecular-Gated Drug Delivery Systems Using Light- DOI: 10.1021/acsabm.0c01458 -
Carboxyl (COOH) confidence 1.0
“cm-1 cm-1/2920 cm-1/2853 cm-1 (ester), 1721 weak triple peak (carboxylic acid), 2963 triple peak (aliphatics), cm-1 and the sixth unresolved one at 3500 (Fig.”
Towards the identification of humic ligands associated with iron transport through a salinity gradient DOI: 10.1038/s41598-022-19618-2 -
Alkyl C-H confidence 1.0
“2963, 2907 cm-1 cm-1 and 2873 were the stretching vibration absorption peaks of saturated C-H, 1730 was the stretching”
Terpolymer resin containing bioinspired borneol and controlled release of camphor: Synthesis and antifouling coating application DOI: 10.1038/s41598-020-67073-8 -
Alkyl C-H confidence 1.0
“The spectrum shows 3030 cm-1, 2963 cm-1, 2925 cm-1, and 2855 cm-1 lines interpreted as stretch C-H vibrations in =CH-, -CH2-”
Bound (“Glassy”) Rubber as a Free Radical Cross-linked Rubber Layer on a Carbon Black DOI: 10.3390/ma11101992
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.