What absorbs at 1272 cm⁻¹ in an FTIR spectrum?
A band near 1272 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 1272 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 |
|---|---|---|---|
| C-O single bond | 11 | 11 | 1.0 |
| Methoxy (OCH3) | 10 | 10 | 1.0 |
| Methacrylate | 10 | 10 | 1.0 |
| Acetate | 10 | 10 | 1.0 |
| Secondary amine | 6 | 6 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| N h | 4 | 4 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Silicon carbon | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 0.9 |
| Amino acid | 1 | 0 | 1.0 |
| N n bond | 1 | 0 | 0.9 |
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 |
|---|---|---|---|
| lignin | 1272, 1035, 1510 | Methacrylate, Acetate, C-O single bond | 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 1272 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
-
Acetate confidence 1.0
“The is attributed to the C O stretchRaman observed at V.Arjunanetal./SpectrochimicaActaPartA 67 (2007) 1290-1296 1295 1272cm-1”
Arjunan 等 - 2007 - Fourier transform infrared and Raman spectral assi DOI: 10.1016/j.saa.2006.09.044 -
Alkyl C-H confidence 1.0
“in Cell-II was assigned by Liang and 710 band at 1420 characteristics of aromatic rings (1604 cm(cid:1)1) cm(cid:1)1 Marchessault23 and a strong absorption at 1272 for to the CH scissoring motion, and 2”
Characterization of chemically modified wood fibers using FTIR spectroscopy for biocomposites DOI: 10.1002/app.31746 -
Amide confidence 1.0
“The FTIR spectrum of the cm-1 cm-1 prepared samples shows peaks at 1272 (C-N stretching) and 1600 (C=N) confirms the bonding of nitrogen cm-1 cm-1 with carbon.”
Karuppannan 和 Prashantha - 2010 - Nano structured carbon nitrides prepared by chemic DOI: 10.1117/12.861609 -
Amide confidence 1.0
“The peak at 1272 is attributed to [University cm-1 C-N.”
Ramesh 等 - 2010 - Synthesis of Nano Structured Carbon Nitride by Pyr DOI: 10.1080/10584587.2010.489421 -
Acetate confidence 1.0
“However, the vibration at the stretching mode of -COOcm-1 v(C-O) and disappearance of the crystalline or amorphous phase with the and at 1272 and at the symmetrical stretching mode cm-1was v presence of lithium salts.”
Effect of lithium salt concentrations on blended 49% poly(methyl methacrylate) grafted natural rubber and poly(methyl methacrylate) based solid polymer electrolyte DOI: 10.1016/j.electacta.2011.06.015 -
Amide confidence 1.0
“cm-1 C-N originates from the stretching vibrations The peak at 1272 TheCPNobtainedwerethenmaintainedata temperatureof±5 °Cfor associated with the oxidation or protonation (doped) states of POT 24 h and washed several times with distilled wa”
Synthesis, characterization and electrochemical behavior of montmorillonite poly(o-toluidine) nanocomposites DOI: 10.1016/j.clay.2013.12.007 -
Protein confidence 1.0
“The chemical maps resulting from the absorption at 1272 (Fig 3 (D)) represent a higher signal in forensic samples, which is commonly attributed to protein αhelix.”
Assessing various Infrared (IR) microscopic imaging techniques for post-mortem interval evaluation of human skeletal remains DOI: 10.1371/journal.pone.0174552 -
Acetate confidence 1.0
“The peaks corresponding to Syringyl, Guaiacyl C-O (1272 cm-1) [30], which are charThe spectrum of char produced at 573 K with a 10 min residence time shows bands cm-1), cm-1 acteristic of softwood lignin, started to diminish clearly.”
Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures DOI: 10.3390/ma14113024
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