What absorbs at 789 cm⁻¹ in an FTIR spectrum?
A band near 789 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 3 cited sources
Hurtigt svar
A band near 789 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 |
|---|---|---|---|
| Silicon carbon | 2 | 2 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Carbohydrate | 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 |
|---|---|---|---|
| PE | 789, 1414, 1700 | Alkyl C-H | 1 |
| PP | 789, 1700, 1043 | Alkyl C-H | 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 789 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
-
Silicon carbon tillid 1,0
“LLM confirmed rule peak-group candidate”
Chen 等 - 2007 - Structural characterization and corrosion properti DOI: 10.4028/www.scientific.net/MSF.546-549.1111 -
Silicon carbon tillid 1,0
“2g) were located at 490 (symmetric Si-O stretch vibration) of the cm-1 cm-1 Si-O-Si chain and 710 (symmetric C-Si-C stretch vibration) and 789 (antisymmetric C-Si-C stretch cm-1 vibration) of the CH 3-Si-CH moieties.”
Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification DOI: 10.1038/s41598-022-23318-2 -
Alkyl C-H tillid 1,0
“in both ester and ether overlapping modes from polysaccharides and alginates in cm-1 The bands at 789 and 840 are attributed to out-of-plane C-H bending (mannose and Aloe) or pyranose ring in [56] and -CH twisting [57-59].”
High-Content Aloe vera Based Hydrogels: Physicochemical and Pharmaceutical Properties DOI: 10.3390/polym15051312
Har du et spektrum med dette bånd?
Upload dit FTIR-spektrum og få en fuld tolkningsrapport — peak-tildelinger med litteraturhenvisninger, biblioteksmatch og en tillidsvurderet beviskæde — på få sekunder.