What absorbs at 657 cm⁻¹ in an FTIR spectrum?
A band near 657 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 657 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.
Возможные назначения функциональных групп
| Функциональная группа | Подтверждающие факты | Цитируемые источники | Максимальная достоверность |
|---|---|---|---|
| Metal oxygen | 3 | 3 | 1,0 |
| Ring structure | 2 | 2 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| C n single bond | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Nitrogen heterocycle | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.
Possible materials
| Материал | Поддерживающие пики | Overlapping groups | Цитируемые источники |
|---|---|---|---|
| TiO2 | 657, 1700, 1093 | Metal oxygen | 1 |
| TiO | 657, 1730, 1699 | Metal oxygen | 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 657 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.
Литература, лежащая в основе этих назначений
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достоверность 1,0
“The Raman peaks observed at 483 are attributed to the stretching mode vibration of Mn-O bonds, and another peak observed at cm-1 657 corresponds to A1g mode vibration of Mn 3O 4.”
Synthesis and characterization of Mn3O4/MnSnO3 nanocomposites for supercapacitor applications DOI: 10.1007/s12588-019-09250-7 -
Alkene (C=C) достоверность 1,0
“The FTIR spectrum showed peaks at 1,592, 1,627 and 1,657 cm-1 assigned to C=C stretching of the imidazole ring and characteristic peaks at 1,605 and 1,766 assigned to C=O stretching.”
Synthesis, Characterization and Reactivity Ratio Study of Poly(di(tri-n-butyltin) citraconate-co-N-vinylimidazole) DOI: 10.3390/molecules15074750 -
достоверность 1,0
“For this same 31, 39, and 46), thus exposing underneath layers, corresamples (showing a gypsum rich content) strong peaks late with the FTIR analysis of the samples, which indiascribed to lead white as well as a sharp peaks around cm-1 cate”
Cortea 等 - 2020 - Uncovering hidden jewels an investigation of the DOI: 10.1186/s40494-020-00401-3 -
Ring structure достоверность 1,0
“The peaks cm-1 cm-1 occurring at 657 and 554 can be associated with the out of plane vibrations of ring structure and C-”
Okeke 等 - 2018 - Characterization of hibiscus sabdariffa fiber as p DOI: 10.1590/S1517-707620180004.0550 -
достоверность 1,0
“Previous researchers have demonstrated that the peak around 657 is attributed 2 cm-1 to Ti-O-Ti stretching vibration, whereas the peak around 590 is due to the vibration of Ti-O-O.”
Physicochemical and Rheological Properties of a Transparent Asphalt Binder Modified with Nano-TiO2 DOI: 10.3390/nano10112152 -
Amide достоверность 1,0
“cm-1 Other bands at 657.1 and 611.8 indicated an O=C-N bend of aliphatic secondary cm-1 amides [38].”
Adsorptive Performance of Walnut Shells Modified with Urea and Surfactant for Cationic Dye Removal DOI: 10.3390/w15081536 -
достоверность 1,0
“In addition, the intense bands seen at 756 657 cm-1 and 489 ascribed to the Ti-O stretching vibration and confirmed the existence of TiO nanoparticles.”
UV-shielding properties of a cost-effective hybrid PMMA-based thin film coatings using TiO2 and ZnO nanoparticles: a comprehensive evaluation DOI: 10.1038/s41598-023-34120-z -
достоверность 0,8
“Characteristic apatite signal”
Mirkovic 等 - 2018 - Structural, Morphological and Electrical Propertie DOI: 10.2298/SOS1801095M
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