What absorbs at 752 cm⁻¹ in an FTIR spectrum?
A band near 752 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 752 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 | 5 | 5 | 1.0 |
| Aromatic ring | 4 | 3 | 1.0 |
| Nitrogen heterocycle | 2 | 0 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 0.7 |
| Ring structure | 1 | 0 | 1.0 |
| C c single bond | 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 |
|---|---|---|---|
| Nanotubes | 752, 1735, 1630 | Alkyl C-H | 1 |
| polystyrene | 752, 1020, 1600 | Aromatic ring, Alkyl C-H | 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 752 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
“LLM confirmed rule peak-group candidate”
Nandiyanto 等 - 2016 - Synthesis of carbon nanoparticles from commerciall DOI: 10.1088/1757-899X/128/1/012042 -
Alkene (C=C) confidence 1.0
“The peak at 2094 is of alkyne stretching viThesurfacemorphologywasinvestigatedbySEM,indicatingthe cm(cid:1)1 CeH brations, and 1632 attendance of sphere-shaped aggregates as silver nanoparticles is for alkene stretch and peak at 752cm(cid:1”
Biogenic Fabrication, Characterization and Drug Loaded Antimicrobial Assay of Silver Nanoparticles Using Centratherum anthalminticum (L.) Kuntze DOI: 10.1016/j.xphs.2021.01.034 -
Aromatic ring confidence 1.0
“The band at 752 was corresponded to ortho 1, 2 substituted benzene rings (Bellamy, 1975).”
Salem 等 - 2019 - Synthesis of compounds having antimicrobial activi DOI: 10.1016/j.bioorg.2019.03.013 -
confidence 1.0
“cm-1 cm-1 The peaks at approximately 1100-1020 and 912 are assigned to stretching at wavenumbers 908 cm-1, 798 cm-1 and 752 cm-1 that can be assigned to the Al-Al-OH, at wavenumbers 908 cm-1, 798 cm-1 and 752 cm-1 that can be assigned to th”
Selectively Etched Halloysite Nanotubes as Performance Booster of Epoxidized Natural Rubber Composites DOI: 10.3390/polym13203536 -
Alkyl C-H confidence 1.0
“1251 1272 1197 1203 Rocking vibrations of the alkyl chains 752”
Bratu 等 - 2011 - New solid form of Norfloxacin Structural studies DOI: 10.3233/SPE-2010-0492 -
Alkyl C-H confidence 1.0
“(C]O) out-ofester group is at The peak of planebendingabsorptionof(C-H)onthearomaticringis 752cm-1.”
Duan 等 - 2021 - Synthesis of highly branched water-soluble polyest DOI: 10.1515/epoly-2021-0004 -
Amide confidence 1.0
“The phosphorylation is demonstrated by the cm(cid:0) P-C 1 (P-O-C or stretching), 974 attributed to the out-of-plane bending mode (C-C-N) (in the reference emergence of weak bands at 752 cm(cid:0)”
Functionalization of poly(glycidylmethacrylate) with iminodiacetate and imino phosphonate groups for enhanced sorption of neodymium - sorption performance and molecular modeling DOI: 10.1016/j.reactfunctpolym.2022.105389 -
Alkyl C-H confidence 1.0
“The absorption bands at 752 (1/cm) - C H correspond to the vibrations of the bonds.”
Hermosillo-Nevarez 等 - 2020 - Feasibility Study on the Use of Recycled Polymers DOI: 10.3390/ma13081824
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