What absorbs at 687 cm⁻¹ in an FTIR spectrum?
A band near 687 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
Brzi odgovor
A band near 687 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.
Moguće dodjele funkcionalnih skupina
| Funkcionalna skupina | Potporni dokazi | Citirani izvori | Najveća pouzdanost |
|---|---|---|---|
| Metal oxygen | 3 | 3 | 1,0 |
| C-O single bond | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Carbonyl (C=O) | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Bromine | 1 | 1 | 1,0 |
| Carbon bromine | 1 | 1 | 1,0 |
Rangiranje odražava akumulirane literaturne dokaze, a ne jedno autoritativno pravilo. Uvijek provjerite u kontekstu vašeg uzorka.
Mogući materijali
| Materijal | Potporni vrhovi | Preklapajuće skupine | Citirani izvori |
|---|---|---|---|
| polypropylene | 687, 1030, 1600 | Alkyl C-H, C-O single bond | 1 |
| TiO2 | 687, 1700, 1093 | Metal oxygen, Alkyl C-H, C-O single bond | 1 |
Materijali su prikazani samo kada ista literatura podržava ovu traku i barem jedan dodatni karakteristični vrh.
Logika spektra
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 687 cm⁻¹ is usually not enough for material identification by itself.
Upotreba u stvarnom svijetu
Ova vrsta upita uobičajena je u identifikaciji polimera, probiru nepoznate plastike, rješavanju problema u kontroli kvalitete, provjeri recikliranog materijala i pregledu dodjele vrhova potkrijepljenom literaturom.
Uobičajene pogreške
- Tretiranje jedne izolirane vrpce kao dokaza materijala bez provjere barem jednog ili dva podržavajuća pika.
- Zanemarivanje preklapanja: više funkcionalnih skupina može doprinositi u blizini istog valnog broja.
- Preskakanje validacije kada aditivi, mješavine, oksidacija ili kontaminacija mogu izobličiti spektar.
Savjet za provjeru
Kada nejasnoća ostane, validirajte hipotezu pomoću DSC, GC-MS ili TGA, posebno za mješavine, degradirane uzorke i punjene polimere.
Literatura iza ovih dodjela
-
Metal oxygen pouzdanost 1,0
“The bands cm-1 cm-1 at 300.9 and 347.19 correspond to M-O stretching mode of the octahedral group, and the cm-1 band at 686.66 corresponds to M-O stretching mode tetrahedral group [8, 11, 13].”
Deswardani 等 - 2017 - Study of Structural and Magnetic Properties of Sil DOI: 10.1088/1757-899X/202/1/012047 -
Carbon bromine pouzdanost 1,0
“LLM confirmed rule peak-group candidate”
Furoida 和 Ulfa - 2019 - Synthesis of 3-(7-triphenylphosphonioheptyl)-2,6-d DOI: 10.1088/1757-899X/546/6/062008 -
Carboxyl (COOH) pouzdanost 1,0
“The new peak at 1591 in acid equilibrated DHOA was assigned to the amide carbonyl 0.8 cm-1 group interacted with the HNO while the peak at 687 3 Intensity 0.7”
Verma 等 - 2018 - Structural investigations on uranium(VI) and thori DOI: 10.1039/C7NJ04460G. -
Metal oxygen pouzdanost 1,0
“This agrees [PO with the phenomena in the quenched melts observed by Wong.[28] There is no evidence for Fe-O-P and Al-O-P bands in the present slags, as the latter type of bands 687.27cm-1 would result in stretch vibrations with Raman bands”
Wang 等 - 2015 - Effect of P2O5 and FetO on the Viscosity and Slag DOI: 10.1007/s11663-014-0270-1 -
Alkyl C-H pouzdanost 1,0
“While the VIS regression coefficient showed a curve profile with a maximal contribution typical of the 8-hydroxyquinoline-Cd(II) complex [54], the FTIR regression coefficient profile included Kelex 100 characteristic IR vibrational bands at”
Determination of Cadmium (II) in Aqueous Solutions by In Situ MID-FTIR-PLS Analysis Using a Polymer Inclusion Membrane-Based Sensor: First Considerations DOI: 10.3390/molecules25153436 -
pouzdanost 1,0
“of the -OH bonds and vibration via deformation of the bonds in adsorbed surface water molecules, of the -OH bonds and vibration via deformation of the bonds in adsorbed surface water molecules, cm-1 The peak located near 687 is characterist”
Metakaolin-Based Geopolymer with Added TiO2 Particles: Physicomechanical Characteristics DOI: 10.3390/coatings7120233 -
Silicon (Si) pouzdanost 1,0
“The bands at 744 and 687 cm-1 are attributed to the perpendicular Si-O stretching vibration.”
Morphology and Selected Properties of Modified Potato Thermoplastic Starch DOI: 10.3390/polym15071762 -
C-O single bond pouzdanost 1,0
“The peak observed at 687 represents C-OH out-of-plane, denoting the presence of cellulose [91-94].”
Characterization of Thermo-Mechanical and Chemical Properties of Polypropylene/Hemp Fiber Biocomposites: Impact of Maleic Anhydride Compatibilizer and Fiber Content DOI: 10.3390/polym15153271
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