What absorbs at 742 cm⁻¹ in an FTIR spectrum?
A band near 742 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
Hurtigt svar
A band near 742 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 |
|---|---|---|---|
| Alkyl C-H | 7 | 7 | 1,0 |
| Methacrylate | 4 | 4 | 1,0 |
| Acetate | 4 | 4 | 1,0 |
| Ketone | 3 | 3 | 1,0 |
| Ester | 3 | 3 | 1,0 |
| Carboxyl (COOH) | 3 | 3 | 1,0 |
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Amide | 3 | 3 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Phosphorus | 1 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Methyl | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| C-S single bond | 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 |
|---|---|---|---|
| PVA | 742, 1660, 2930 | Alkyl C-H, Acetate, Methacrylate | 1 |
| Epoxy | 742, 1660, 1735 | Methacrylate, Acetate, Alkyl C-H | 1 |
| CaO | 742, 2909, 1839 | Methacrylate, Acetate | 1 |
| polyurethane | 742, 2270, 1700 | Alkyl C-H, Methacrylate, Acetate | 1 |
| PLA | 742, 1650, 1073 | Alkyl C-H, Methacrylate, Acetate | 1 |
| epoxy resin | 742, 905, 1100 | Methacrylate, Acetate, 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 742 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
“The band at cm-1 742 is probably due to the Ca-O bonds [7].”
Characterization of quicklime as raw material to hydrated lime: Effect of temperature on its characteristics DOI: 10.1063/1.5066668 -
C-S single bond tillid 1,0
“LLM confirmed rule peak-group candidate”
Mesoporous Magnetic Cysteine Functionalized Chitosan Nanocomposite for Selective Uranyl Ions Sorption: Experimental, Structural Characterization, and Mechanistic Studies DOI: 10.3390/polym14132568 -
Carbonyl (C=O) tillid 1,0
“The corresponding light minus dark FTIR difference spectrum ν(C=O) (Figure 4, in the region black line) shows a sigmoidal cm-1 and a positive peak at band with a negative peak at 1,742 cm-1, that are absent in the difference spectrum of the”
Baserga 等 - 2022 - Membrane Protein Activity Induces Specific Molecul DOI: 10.3389/fmolb.2022.915328 -
Acetate tillid 1,0
“The band at 742 cm-1 is assigned to the CH3 rocking cm-1 CH rocking mode, while 596 and 562 are related to [ νasGa-C 2] and [ νsGa-C 2].”
Synthesis of High Surface Area—Group 13—Metal Oxides via Atomic Layer Deposition on Mesoporous Silica DOI: 10.3390/nano12091458 -
Acetate tillid 1,0
“cm-1, cm-1, cm-1, cm-1, C-CH3 stretching at 1042-1046 cm-1, C-COO vibration assigned to 873 cm-1, (possibly due to the to 1095-1098 C-CH stretching at 1042-1046 C-COO vibration assigned to 873 3 cm-1, presence of CaCO3), C=O stretching assi”
Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure DOI: 10.3390/app7060579 -
C c single bond tillid 1,0
“The third one at 1477 cm-1 was associated with CH-cross deformations in CH 2-groups and the fourth band at 742 cm-1 was assigned to H-C-C-H-bound modes in the CH groups.”
Fernández 等 - 2017 - DOI: 10.17230/ingciencia.13.25.6 -
Phosphate (PO4) tillid 1,0
“The bending modes of the P-O bonds in phosphate groups are responsible for the double peak at 563 and 742 cm-1.”
Synthesis and Characterization of New Composite Materials Based on Magnesium Phosphate Cement for Fluoride Retention DOI: 10.3390/ma16020718 -
Acetate tillid 1,0
“cm-1 (imide carbonyl asymmetric stretching), 1715 (imide carbonyl symmetric stretchcm-1 ing and C=O stretching of carboxylic pendant groups), 1370 (C-N stretching), and cm-1 cm-1 742 (C=O bending).”
Novel Polyimide/Copper-Nickel Ferrite Composites with Tunable Magnetic and Dielectric Properties DOI: 10.3390/polym
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