What absorbs at 1279 cm⁻¹ in an FTIR spectrum?
A band near 1279 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 1279 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 | 5 | 4 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 2 | 1.0 |
| Methacrylate | 3 | 2 | 1.0 |
| Acetate | 3 | 2 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 0.8 |
| Hydroxyl (O-H) | 1 | 0 | 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 |
|---|---|---|---|
| TiO2 nanoparticles | 1279, 1700, 455 | Alkyl C-H, Methacrylate, C-O single bond | 2 |
| PEG | 1279, 1650, 1342 | Alkyl C-H, Methacrylate, C-O single bond | 1 |
| TiO2 | 1279, 1700, 1093 | Alkyl C-H, Methacrylate, C-O single bond | 1 |
| TiO | 1279, 1730, 1699 | 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 1279 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
-
Carbonyl (C=O) confidence 1.0
“platensis grown photoautotrophically under nitrogen cm-1 and 1279 for the carbonyl (C=O) stretching of the ester (-N).”
Enhanced polyhydroxybutyrate (PHB) accumulation in heterotrophically grown Arthrospira platensis under nitrogen deprivation DOI: 10.1007/s10811-020-02272-4 -
Carboxyl (COOH) confidence 1.0
“The frequency values of this band was higher for example, the ratios of dipicolinic acid band or the marker band 1279cm(cid:2)1 1545cm(cid:2)1 and (Amide II band) (Helm & Naumann, (1744.94±1.55) for Micrococcus species compared to Bacillus”
Use of Fourier transform infrared spectroscopy for rapid comparative analysis of Bacillus and Micrococcus isolates DOI: 10.1016/j.foodchem.2008.08.063 -
Alkyl C-H confidence 1.0
“AM-3 Compound exhibited characteristic peaks at 2790.07, 1443.55 (C-C stretching vibration of thiophene), 1357.21 (C-N and N-N stretching vibration), 1278.82 (in-plane C-H stretching vibration cm-1,”
Novel Hemocompatible Imine Compounds as Alternatives for Antimicrobial Therapy in Pharmaceutical Application DOI: 10.3390/pr8111476 -
Ring structure confidence 1.0
“(cm-1) Frequency Band Assignment Species C-H 929 out-of-plane deformation 1018 Ring deformation 1081 Furfural 1156 =C-O-C= ring vibration 1279 1570 C=C stretches 1696 C=O aldehyde stretch 1671 C-O 1163 acid stretch vibration 1369 CH symmetr”
Solubility Temperature Dependence of Bio-Based Levulinic Acid, Furfural, and Hydroxymethylfurfural in Water, Nonpolar, Polar Aprotic and Protic Solvents DOI: 10.3390/pr9060924 -
C-O single bond confidence 1.0
“at 1279, 1254 and 1239 bending vibrations d(C-OH) Additionally, the stoichiometric ratio between Ti of the phenolic group at 1365, 1184, 1163, and surf”
Jankovic 等 - 2010 - New Hybrid Properties of TiO2 Nanoparticles Surfac DOI: 10.1007/s11671-009-9447-y -
Ester confidence 1.0
“Characterisation of Extracted Polyester The characteristic wave numbers of PHB in the FTIR spectrum were presented by the cm-1 strong carbonyl group (C=O) at 1726 and asymmetric C-O-C stretching vibration cm-1, at 1279 which are typical for”
Leptolyngbya sp. NIVA-CYA 255, a Promising Candidate for Poly(3-hydroxybutyrate) Production under Mixotrophic Deficiency Conditions DOI: 10.3390/biom12040504 -
Alkyl C-H confidence 1.0
“The bands that appeared cm-1 at 1279 and 1229 correspond to C-H twisting vibrations.”
FTIR and Raman Characterization of TiO2 Nanoparticles Coated with Polyethylene Glycol as Carrier for 2-Methoxyestradiol DOI: 10.3390/app7010049 -
confidence 1.0
“~1461 and 1471 (C-H (C-Cl stretching 8 (stretching vibration of methylene C-H bending vibrations), vibrations), the N-H amino group) group-bond stretching ~1279, 1099 and 1077 ~600 (C-Br and cleavage)”
Markowicz 和 Szymanska-Pulikowska - 2021 - Assessment of the Decomposition of Oxoand Biodeg DOI: 10.3390/ma14216449
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