What absorbs at 3126 cm⁻¹ in an FTIR spectrum?
A band near 3126 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
Quick answer
A band near 3126 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 | 3 | 2 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| AuNPs | 3126, 1646, 1721 | Hydroxyl (O-H), Alkyl C-H | 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 3126 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
“N-H peaks in the complexed materials are the stretching shifts in 3126cm-1 3028cm-1 4+ NH from to and that of the bending mode 1441cm-1 1433cm-1 H-N-H 0.001 of from to when 30 wt.”
Synthesis and characterizations of phthaloyl chitosan-based polymer electrolytes DOI: 10.1016/j.jnoncrysol.2012.04.019 -
Ammonium confidence 1.0
“However, as the salt concentration increased, this band broadened further until a small sharp peak appeared at 3126 cm-1, possibly due to the aggregation of excess ammonium salt-forming salt agglomerates in the polymer matrix.”
Substantial Proton Ion Conduction in Methylcellulose/Pectin/Ammonium Chloride Based Solid Nanocomposite Polymer Electrolytes: Effect of ZnO Nanofiller DOI: 10.3390/membranes12070706 -
Alkyl C-H confidence 1.0
“yellow solid, mp IR: 1502, 1541, 1600 aromatic spectrometer using CDCl as solvent and TMS as the internal stand- (C=O 3 cm-1 stretch), 1731 stretch), 2981 (C-H aliphatic stretch), 3126 ard.”
Nikpassand 等 - 2017 - Green synthesis of novel 2-pyrazolyl-1,3-thiazolid DOI: 10.1515/hc-2017-0124 -
Hydroxyl (O-H) confidence 1.0
“The IR spectrum of PUE cm-1 displayed band at 3330, 3227 for hydroxyl stretching vibration, 3126 and 2901 attributable to aromatic vibrational C-H, although 1627 confirm the existence of C= O with strong peaks of -C=C stretching vibration a”
Puerarin-coated gold nanoparticles (PUE-AuNPs) synthesized via green synthetic route: a new colorimetric probe for the detection of ciprofloxacin DOI: 10.3906/kim-2106-4 -
confidence 0.5
“Part of range 3450-3126; no explicit assignment.”
Xu 等 - 2019 - Enhancement of an organic-metallic hybrid charring DOI: 10.1098/rsos.181413
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