What absorbs at 3128 cm⁻¹ in an FTIR spectrum?
A band near 3128 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 | 2 | 2 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
C=n confidence 1.0
“ring),1547cm-1 stretching,1709cm-1,1706cm-1,1705cm-1 for (b), (c) due to C=C bond for (a),(b),(c) pyrrole 3161cm-1 (a),3399cm-1 3127cm-1for (b),3362cm-1 3128cm-1 respectively due to C=N stretching, for and and for (c) are assigned to the pr”
Synthesis, characterization, morphological and electrical studies of polypyrrole nanostructures DOI: 10.1063/1.5093829 -
Water (H2O) confidence 1.0
“3b, absorption peaks at 3128 and 1638 are the stretching vibration of -OH and the deformation vibration of bound water respectively.”
Hu 等 - 2021 - Pyrolytic Characteristics and Kinetics of Guanzhon DOI: 10.1016/j.fuel.2014.01.014 -
Alkyl C-H confidence 1.0
“yield 84% of 4-yl)thiazolidin-4-one (4i) δ 263-265°C: cm-1 1H aliphatic stretch), 3128 (C-H aromatic stretch);”
Nikpassand 等 - 2017 - Green synthesis of novel 2-pyrazolyl-1,3-thiazolid DOI: 10.1515/hc-2017-0124 -
confidence 1.0
“peak at 3128 cm-1 cm-1 was attributed to N-H stretching vibration;”
In Vitro Interaction of Doxorubicin-Loaded Silk Sericin Nanocarriers with MCF-7 Breast Cancer Cells Leads to DNA Damage DOI: 10.3390/polym13132047 -
Alkyl C-H confidence 1.0
“2881, 2942, 2970 2881, 2942, 2969 3127 (cation ring C-H vibration) 3128 3128 3128”
Verma 等 - 2012 - Effect of Ultrasonic Irradiation on Preparation an DOI: 10.1155/2012/570719
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