What absorbs at 3045 cm⁻¹ in an FTIR spectrum?
A band near 3045 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 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.
可能的官能团归属
| 官能团 | 支持性事实 | 引用来源 | 最高置信度 |
|---|---|---|---|
| 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 |
排名反映了累积的文献证据，而非单一的权威规则。请始终对照您的样品背景进行确认。
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.
这些分配背后的文献
-
Alkyl C-H 置信度 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) 置信度 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 置信度 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 置信度 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 置信度 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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