What absorbs at 1179 cm⁻¹ in an FTIR spectrum?
A band near 1179 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 1179 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) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 1 | 0.9 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.9 |
| Carbonyl (C=O) | 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 |
|---|---|---|---|
| kraft lignin | 1179, 1744, 1710 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| PVC | 1179, 834, 1195 | Methoxy (OCH3), Methacrylate, Acetate | 1 |
| PVDF | 1179, 1160, 840 | Methacrylate, Acetate | 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 1179 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
“1 FTIR spectrum of (a) Ca-MS nanohybrid, (b) Ca-MS end-capped PCL, (c) TEM image of Ca-MS nanohybrid 1 3 Polymer Bulletin cm-1 appeared at 1179 is assigned to C-O-C stretching of PCL.”
Thermal degradation and crystallization kinetics studies on synthesized calcium mercaptosuccinate end-capped poly(ε-caprolactone) nanocomposite DOI: 10.1007/s00289-018-2614-5 -
Nitrogen heterocycle confidence 1.0
“Strong hydrogen bonding two imodazole nitrogens of His side chains were specifically labeled with 2600-3000 cm-1, of the imidazole NH was shown by (i) the presence of several peaks at which arise from Fermi resonance of harmonics or combina”
Noguchi 等 - 1999 - Hydrogen bonding interaction between the primary q DOI: 10.1021/bi982294v -
Fluorine (C-F) confidence 1.0
“Explicitly stated: 'symmetric stretching vibrations of CF were ascribed to the bands that occurred at 1179'.”
Ramadan 和 Ismail - 2022 - Tunning the Physical Properties of PVDFPVCZinc F DOI: 10.21203/rs.3.rs-935328/v1 -
Acetate confidence 1.0
“Peak at 1147 is attributes to CH bending and the peak at 1179 shows C-O-C bending.”
Bhattacharyya 等 - 2017 - Metallization and APPJ treatment of bismaleimide DOI: 10.1155/2010/987357 -
Amide confidence 1.0
“The presence of the cm-1 bands at 1179, 1031, 739, and 689 corresponding to C-N and C-H vibrations from the benzenoid and quinoid section of PANI confirm the presence of the polymer in the PVA matrix.”
Purification and Glutaraldehyde Activation Study on HCl-Doped PVA–PANI Copolymers with Different Aniline Concentrations DOI: 10.3390/molecules24010063 -
Hydroxyl (O-H) confidence 1.0
“C-C, C=C (aromatic skeleton), stretching C-C, C=C (aromatic skeleton), stretching 1379 1379 - - 1396 1379 1379 - - 1396 - - - 1271 1270 1272 C-O (guaiacyl unit) stretching - - - 1271 1270 1272 C-O (guaiacyl unit) stretching - - - 1219 1221”
Activation of Magnesium Lignosulfonate and Kraft Lignin: Influence on the Properties of Phenolic Resin-Based Composites for Potential Applications in Abrasive Materials DOI: 10.3390/ijms18061224 -
Acetate confidence 1.0
“In Figure 10, the IR spectrum of (BX)2 contains intensive symmetric stretching vibration of In Figure 10, the IR spectrum of (BX)2 contains intensive symmetric stretching vibration of C-O-C with peak frequencies at 1157 and 1179 cm-1.”
Yu 等 - 2016 - The Desulfurization of Magnetite Ore by Flotation DOI: 10.3390/min6030070 -
Phosphate (PO4) confidence 0.9
“Text: 'peak (1179 P=O)'”
Oliveira 等 - 2017 - Chemical Interaction Analysis of an Adhesive Conta DOI: 10.2341/16-062-L
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