What absorbs at 758 cm⁻¹ in an FTIR spectrum?
A band near 758 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 758 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 | 6 | 6 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Oxygen heterocycle | 2 | 2 | 0.9 |
| Amide | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 0 | 0.7 |
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 |
|---|---|---|---|
| polyvinylpyrrolidone | 758, 1660, 1700 | Amide, Alkyl C-H | 1 |
| PVP | 758, 2983, 1648 | Alkyl C-H, Amide | 1 |
| ZnO nanoparticles | 758, 1219, 1726 | Alkyl C-H, Amide | 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 758 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
“Out of plane symmetric deformation in NO and out of plane bending in C-H vibrations are 2 cm-1, observed at 758 and 829, 853 respectively, in IR spectra.”
Dalal 等 - 2015 - Structural, electrical, ferroelectric and mechanic DOI: 10.1039/C5RA10501C. -
Acetate confidence 1.0
“The peak at 758 can be attributed to the C-O bond stretching.”
Khan 等 - 2016 - Sol-gel synthesis of thorn-like ZnO nanoparticles DOI: 10.1038/srep27689 -
C-S single bond confidence 1.0
“1,091 and 1,051 The absorption bands around 758 cm-1 and 653 observed in the FTIR spectra of the monomer C-S and polymer are characteristic of stretching mode of A B Fig.”
Raj 等 - 2010 - Synthesis and characterization of novel nano-size DOI: 10.1007/s11581-009-0328-2 -
Hydroxyl (O-H) confidence 1.0
“However, the large deviation of experimental C-H and O-H stretching 758cm-1 vibrations with the DFT peaks as shown in Figure 3 has been peak, which is clearly marked with its value in addressed by Ullah et al.”
Ullah 等 - 2016 - Fourier Transform Infrared Spectroscopy of Bisphe DOI: 10.1155/2016/2073613 -
Aromatic ring confidence 1.0
“Inordertomakeaconvenientdiscussion,thewholespectrumis CeH 1e2vinyl olefinic 910 bending vibration groups CeH CeHbending divided into three parts: the hydroxyl and stretching region 758 Aromatic vibration Phenylgroups cm(cid:1)1),”
Thermal ageing behavior of styrene-butadiene random copolymer: A study on the ageing mechanism and relaxation properties DOI: 10.1016/j.polymdegradstab.2012.06.015 -
Alkyl C-H confidence 1.0
“N c h The FTIR spectra of complex A showed an absorption i k c l h c g cm-1 c band at 758 corresponding to adjacent H atom of c g”
Aiad 等 - 2012 - Synthesis and Biocidal Activity of Some Naphthalen DOI: 10.1007/s11743-011-1286-z -
Aromatic ring confidence 1.0
“The peak at 757.67 indicates to the existence of aromatic ring alkanes.”
Pyrolysis of Solid Waste for Bio-Oil and Char Production in Refugees’ Camp: A Case Study DOI: 10.3390/en14133861 -
C c single bond confidence 1.0
“The peak at 758 800 (cid:3)C for all the PVP amount exhibit and also is assigned to the C-C”
Alibe 等 - 2019 - Effects of polyvinylpyrrolidone on structural and DOI: 10.1007/s10973-018-7874-7
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