What absorbs at 725 cm⁻¹ in an FTIR spectrum?
A band near 725 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 725 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.
可能的官能团归属
| 官能团 | 支持性事实 | 引用来源 | 最高置信度 |
|---|---|---|---|
| Alkyl C-H | 9 | 9 | 1.0 |
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Sulfur | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Imide | 1 | 0 | 1.0 |
| Secondary amine | 1 | 0 | 1.0 |
| C n single bond | 1 | 0 | 1.0 |
| Amide | 1 | 0 | 1.0 |
| Ammonium | 1 | 0 | 1.0 |
排名反映了累积的文献证据，而非单一的权威规则。请始终对照您的样品背景进行确认。
Possible materials
| 材料 | 支持峰 | Overlapping groups | 引用来源 |
|---|---|---|---|
| PET | 725, 1408, 800 | Methacrylate, Alkyl C-H, Methoxy (OCH3) | 1 |
| Nanotubes | 725, 1735, 1630 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 1 |
| nanotube | 725, 1540, 1080 | Methacrylate, Alkyl C-H | 1 |
| kaolinite | 725, 3696, 693 | Silicon-oxygen (Si-O) | 1 |
| bitumen | 725, 1625, 810 | Alkyl C-H | 1 |
| oil | 725, 1161, 1163 | Alkyl C-H, Methoxy (OCH3), Methacrylate | 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 725 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.
这些分配背后的文献
-
Alkyl C-H 置信度 1.0
“At peak ~725 peak signifies the present of C-H bond from glucose”
Aziz 等 - 2018 - The effect of Pineapple Leaf Fiber (PALF) incorpor DOI: 10.1088/1755-1315/105/1/012082 -
Aromatic ring 置信度 1.0
“LLM confirmed rule peak-group candidate”
Covalent diphenylalanine peptide nanotube conjugated to folic acid/magnetic nanoparticles for anti-cancer drug delivery DOI: 10.1016/j.jddst.2017.06.005 -
C c single bond 置信度 1.0
“Also, cm-1 cm-1 and 686 [48, 50] as well as strong C-C stretching of sharp and strong peaks at 725”
Jevremovic 等 - 2014 - Investigation of the effect of acid dopant on the DOI: 10.1016/j.cap.2014.06.018 -
Alkyl C-H 置信度 1.0
“LLM confirmed rule peak-group candidate”
Sanchez-Lemus 等 - 2016 - Characterization of Heavy Distillation Cuts Using DOI: 10.1021/acs.energyfuels.6b01912 -
置信度 1.0
“Apart from this obvious change in the sample hydration on heating to 1100°C, small changes also occur cm-1 in the Al-Si-O region, especially the development of the broad zeolites band at about 725 (see”
Souissi 等 - 2022 - Synthesis, Thermal Properties and Electrical Condu DOI: 10.21203/rs.3.rs-1294285/v1 -
Alkyl C-H 置信度 1.0
“of cm(cid:0) 1 = (cid:0) cis-HC bration) and peak at 725 (attributed to CH bending (cid:0)0.961** parameters (cid:0)0.739* (cid:0)0.721* AV -(CH2)nFatty rocking vibration).”
Impact of microwave roasting on physicochemical properties, maillard reaction products, antioxidant activity and oxidative stability of nigella seed (Nigella sativa L.) oil DOI: 10.1016/j.foodchem.2021.130777 -
置信度 1.0
“The reductions in peak intensity in the regions 3750-3600 cm-1 and 825725 cm-1 were attributed to decreased numbers of Al-OH structures, while the increased 725 cm-1 were attributed to decreased numbers of Al-OH structures, while the increa”
Selectively Etched Halloysite Nanotubes as Performance Booster of Epoxidized Natural Rubber Composites DOI: 10.3390/polym13203536 -
Alkyl C-H 置信度 1.0
“2 cm-1 cm-1 peak at 1161 and shoulder peaks at 1095 and 1237 (attributed to stretching cm-1 vibration of C-O ester groups of the triglycerides) and peak at 725 (associated with outof-plane vibration of cis -HC=CH-group of disubstituted olef”
Impact of infrared and dry air roasting on the oxidative stability, fatty acid composition, Maillard reaction products and other chemical properties of black cumin (Nigella sativa L.) seed oil DOI: 10.1016/j.foodchem.2019.05.140
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