What absorbs at 1264 cm⁻¹ in an FTIR spectrum?
A band near 1264 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 1264 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 |
|---|---|---|---|
| Methoxy (OCH3) | 9 | 8 | 1.0 |
| Methacrylate | 9 | 8 | 1.0 |
| Acetate | 9 | 8 | 1.0 |
| C-O single bond | 9 | 8 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Lignin | 2 | 2 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 1264 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
-
Alkyl C-H confidence 1.0
“The peak at 1264 Phytonanocomposite indicates the presence of strong methyl bond.”
Synthesis of Phytonanocomposite of Zinc Oxide by Ixora coccinea Linn for Cancer Treatment DOI: 10.1007/s10904-016-0382-y -
Borate confidence 1.0
“The mode at 1264 is likely due B-O vibrational motions in the molecule, while the to imperfections in the gold surface allowing the silicon”
Brewer 等 - 2004 - Infrared detection of a phenylboronic acid termina DOI: 10.1021/la035037m -
Ester confidence 1.0
“cm-1 The vibration peak near 1264 is attributed to esters from DOTP in C-1.”
Synthesis, characterization and thermal behavior of plasticized poly (vinyl chloride) doped with folic acid-modified titanium dioxide DOI: 10.1038/s41598-022-07177-5 -
Lignin confidence 1.0
“1245, and 1125 The lignin band at 1264 cm(cid:1)1, obwhich was not visible in the spectra tained from undecayed beech wood, developed”
Examination of the lignin content in a softwood and a hardwood decayed by a brown-rot fungus with the acetyl bromide method and Fourier transform infrared spectroscopy DOI: 10.1002/pola.20071 -
Amide confidence 1.0
“cm-1, Another stretching vibration is observed at 1264 which is characteristic of C-N stretching, which is attributable to the PVP [43] residue remaining from”
The effect of Ag nanoparticles in Ag/polyvinyl alcohol nanofiber composites DOI: 10.1007/s00289-020-03528-2 -
Ketone confidence 1.0
“1628 Ketone stretch ketone) C@O 1264?1302cm(cid:2)1, ?1394cm(cid:2)1, COO(cid:2) (m ? (Fig.”
Adsorption of Enrofloxacin on montmorillonite: Two-dimensional correlation ATR/FTIR spectroscopy study DOI: 10.1016/j.jcis.2012.09.039 -
Carbonyl (C=O) confidence 1.0
“The polymerization of the SI-PDEAEMA_exf.GO_2 is observed at 1450 and 1384 3 iley.com cm-1 (2 mL exfoliated SI-GO dispersion was used during polymerizaThe peaks at 1264 and 1146 correspond to the CO tion) sample was conducted within 5 days”
Aliyev 等 - 2020 - SI-ATRP Polymer-Functionalized Graphene Oxide for DOI: 10.1002/admi.202000443. -
Acetate confidence 1.0
“Strong and medium strong bands at 1264 and 1234 have been attributed cm-1 cm-1 to C-O stretching vibrations, respectively.”
Multivariate Data Analysis and Central Composite Design-Oriented Optimization of Solid Carriers for Formulation of Curcumin-Loaded Solid SNEDDS: Dissolution and Bioavailability Assessment DOI: 10.3390/pharmaceutics14112395
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