What absorbs at 3045 cm⁻¹ in an FTIR spectrum?
Una banda cerca de 3045 cm⁻¹ puede apuntar a varios grupos funcionales. A continuación se muestran las asignaciones más probables, clasificadas por cuánta evidencia publicada respalda cada una — cada una trazable a literatura (DOI) y validada de forma cruzada con nuestros más de 130,000 espectros de referencia y grafo de conocimiento.
Backed by 5 cited sources
Quick answer
A band near 3045 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.
Posibles asignaciones de grupos funcionales
| Grupo funcional | Hechos de respaldo | Fuentes citadas | Confianza máxima |
|---|---|---|---|
| Alkyl C-H | 3 | 3 | 1,0 |
| Aromatic ring | 2 | 2 | 1,0 |
| Sulfur heterocycle | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Ammonium | 1 | 1 | 0,9 |
| N h | 1 | 1 | 0,7 |
La clasificación refleja la evidencia acumulada de la literatura, no una única regla autorizada. Siempre confirme según el contexto de su muestra.
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 3045 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.
Literatura detrás de estas asignaciones
-
Alkyl C-H confianza 1,0
“C-H stretching (alkene/aromatic) 3090, 3114 and 3124 2879, 2940 and 2967 C-H stretching (alkane) 3045, 3055 2940, 2968 C-H stretching (alkane, CH 2-O, CH 2-N)”
Yusoff 等 - 2018 - Theoretical and Experimental Approach Towards P-Cy DOI: 10.1088/1757-899X/374/1/012086 -
Alkene (C=C) confianza 1,0
“α-[4-(2anthraceneiminomethylidene)-phenoxy]-ω-[4-oxybenzaldehyde]-octane cm-1): ν, FTIR (KBr, 3045 (=C-H stretch of the aromatic rings), 2936 - 2856 (C-H stretch of aliphatic chains), 1683 (-CH=O), 1630 (-N=CHstretch), 1604, 1576, 1509 (C-C”
Mesomorphic Behavior of Symmetric Azomethine Dimers Containing Different Chromophore Groups DOI: 10.3390/molecules26082183 -
Alkyl C-H confianza 1,0
“There cm-1 was an intense band at 3300 assigned to NH stretching vibrations of urea moieties, cm-1 cm-1 and several weak bands at ~3105 (=CH stretching in thiophene ring), ~3045”
Voltammetric Detection of Vanillylmandelic Acid and Homovanillic Acid Using Urea-Derivative-Modified Graphite Electrode DOI: 10.3390/s23073727 -
Ammonium confianza 0,9
“Absorption peak for ammonium”
Yu 等 - 2018 - Fast screening compositions of PM2.5 by ATR-FTIR DOI: 10.1016/j.jes.2017.11.021 -
N h confianza 0,7
“Text: 'two poor peaks at 3045 and 1666 are triggered by the overflow Cu2+ N-H'”
Geng 等 - 2021 - Facile Fabrication of a Novel Copper Nanozyme for DOI: 10.1021/acsomega.0c05925
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