What absorbs at 791 cm⁻¹ in an FTIR spectrum?
A band near 791 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 7 cited sources
Hurtigt svar
A band near 791 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.
Mulige funktionelle gruppetildelinger
| Funktionel gruppe | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| Siloxane (Si-O-Si) | 3 | 3 | 1,0 |
| Silicon carbon | 3 | 3 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
Rangering afspejler akkumulerede litteraturbeviser, ikke en enkelt autoritativ regel. Bekræft altid mod din prøvekontekst.
Mulige materialer
| Materiale | Understøttende toppe | Overlappende grupper | Citerede kilder |
|---|---|---|---|
| SiC | 791, 805, 1136 | Silicon carbon, Silicon-oxygen (Si-O), Siloxane (Si-O-Si) | 2 |
| quartz | 791, 800, 3053 | Silicon-oxygen (Si-O), Siloxane (Si-O-Si) | 1 |
Materialer vises kun, når den samme litteraturpulje understøtter dette bånd og mindst en yderligere karakteristisk top.
Spektrumlogik
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 791 cm⁻¹ is usually not enough for material identification by itself.
Anvendelse i virkeligheden
Denne type forespørgsel er almindelig ved polymeridentifikation, screening af ukendt plast, fejlfinding i kvalitetskontrol, verifikation af genanvendt materiale og litteraturunderstøttet gennemgang af peak-tildeling.
Almindelige fejl
- Behandling af et isoleret bånd som bevis på et materiale uden at kontrollere mindst en eller to understøttende toppe.
- Ignorerer overlap: flere funktionelle grupper kan bidrage nær samme bølgetal.
- Spring validering over, når additiver, blandinger, oxidation eller forurening kan forvrænge spektret.
Verifikationsrådgivning
Når tvetydighed fortsat består, valider hypotesen med DSC, GC-MS eller TGA, især for blandinger, nedbrudte prøver og fyldte polymerer.
Litteratur bag disse tildelinger
-
tillid 1,0
“showed the characteristic vibration of SiC at 791 Peaks cm-1 Si-O-Si Opositioned at 473 and 1102 were assigned to and 2.4.”
In situ formation of β-silicon carbide nanorods from the hybrid of an organic moiety and methyltriethoxysilane DOI: 10.1016/j.matlet.2011.04.040 -
Alkyl C-H tillid 1,0
“The absorption peak at 791 is characpyrimidine ring, and the stretching and swinging of the C H and cm-1 terized by the collective vibrations of four molecules in the lattice, H bonds.”
A comparative study on the experimental and calculated results of mid-infrared and Raman vibrational modes of nucleic acid bases DOI: 10.1016/j.jmgm.2017.04.016 -
Silicon carbon tillid 1,0
“cmthe bending CH3 groups originating from Si-CH3 bond, Si-O-Si groups (1089-1015 weight - 60.10, vapor density - 2.1 (vs air), vapor pressure - 33 mmHg (20°C) and 44 (791cm-1) 1) and the stretch Si-C bonds from CH3 in the case of ZnO/PDMS p”
Sonmez 等 - 2018 - IDENTIFYING THE OPTIMUM METHOD FOR MODIFYING THE Z DOI: 10.1016/j.apcata.2012.03.037. -
Ring structure tillid 1,0
“Borate ring deformation (662 1), cm-1), BO bending (791 stretching vibration of 3”
Vasumathy 等 - 2016 - Preparation and Characterization of the Structural DOI: 10.1590/1980-5373-MR-2016-0014 -
Silicon carbon tillid 0,9
“Explicit assignment: characteristic vibration of SiC at 791 cm-1.”
Growth of silicon carbide nanorods from the hybrid of lignin and polysiloxane using sol-gel process and polymer blend technique DOI: 10.1016/j.matlet.2009.08.029 -
Siloxane (Si-O-Si) tillid 0,9
“explicit assignment in text”
Evaluation of polyvinyl alcohol–borax/agarose (PVA–B/AG) blend hydrogels for removal of deteriorated consolidants from ancient Egyptian wall paintings DOI: 10.1186/s40494-019-0264-z -
tillid 0,7
“out-of-plane polymers”
The effect of chain extender structure on the properties of new thermoplastic poly(carbonate–urethane)s derived from MDI DOI: 10.1007/s10973-016-5756-4
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