What absorbs at 974 cm⁻¹ in an FTIR spectrum?
A band near 974 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
Quick answer
A band near 974 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.
Possíveis atribuições de grupos funcionais
| Grupo funcional | Fatos de suporte | Fontes citadas | Maior confiança |
|---|---|---|---|
| Alkyl C-H | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| C c single bond | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Phosphate (PO4) | 2 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| Nucleic acid | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Silanol (Si-OH) | 1 | 1 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 0,9 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Possible materials
| Material | Picos de suporte | Overlapping groups | Fontes citadas |
|---|---|---|---|
| PE | 974, 1414, 1700 | Alkyl C-H | 1 |
| PP | 974, 1700, 1043 | Alkyl C-H | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
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 974 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 por trás destas atribuições
-
C c single bond confiança 1,0
“In the difference spectrum between before and cm-1 in L stretching vibration of the chromophore at 1192 (350-500 after the illumination with blue light nm) (Figure has exactly the same intensity in both difference spectra C-C cm-1, a 2a), i”
Maeda 等 - 1999 - Chromophore-protein-water interactions in the L in DOI: 10.1021/bi9907072 -
Hydroxyl (O-H) confiança 1,0
“030068-1 RESULTS AND DISCUSSION The FTIR spectrum of pure and Cr doped synthesized samples were carried out by using Bruker Tensor-27 Fourier cm-1 (wavenumber) using KBr pellets shown Transform-Infrared Spectrophotometer (FTIR) in the range”
Rani 和 Yadav - 2015 - Study of Optical Properties of BaMn1-xCrxO3 (x=0.0 DOI: 10.1063/1.4929284 -
confiança 1,0
“For the BR spectrum (e), the D 2O-sensitive intense bands at 974 (+) (+) cm-1 and 957 were assigned as HOOP vibrations C15-H N-H (44), of and groups indicating that the”
Suzuki 等 - 2008 - Structural Changes of Salinibacter Sensory Rhodops DOI: 10.1021/bi801358b -
Silanol (Si-OH) confiança 1,0
“The presence of a band at 974 indiwater, and followed by hot water several times in order to cated the Si-OH stretching vibration in the parent silica Na+, remove and oven dried at 383 K for 24 h.”
Adam 等 - 2012 - Liquid Phase Oxidation of Acetophenone over Rice H DOI: 10.1016/S1872-2067(11)60361-6 -
Alkyl C-H confiança 1,0
“2 cm-1 cm-1 tion vibrations, and bands at 974 and 999 to CH deformation vibrations.”
Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification DOI: 10.1038/s41598-022-23318-2 -
C c single bond confiança 1,0
“The phosphorylation is demonstrated by the cm(cid:0) P-C 1 (P-O-C or stretching), 974 attributed to the out-of-plane bending mode (C-C-N) (in the reference emergence of weak bands at 752 cm(cid:0)”
Functionalization of poly(glycidylmethacrylate) with iminodiacetate and imino phosphonate groups for enhanced sorption of neodymium - sorption performance and molecular modeling DOI: 10.1016/j.reactfunctpolym.2022.105389 -
Ring structure confiança 1,0
“In addition, the Raman peak at 974 for layers #2 and #5 (shown by a double asterisk δ(CNC) δ(NCN), in Figure 4) is characteristic of the ring breathing modes, i.e., and of the substituted triazine ring of melamine [37,38].”
Multi-Modal Compositional Analysis of Layered Paint Chips of Automobiles by the Combined Application of ATR-FTIR Imaging, Raman Microspectrometry, and SEM/EDX DOI: 10.3390/molecules24071381 -
Nucleic acid confiança 1,0
“a significant decrease in the ratio from the right to left ischemic ventricles, reaching quantified by the nucleic acid/protein indicator (band area ratio 974 cm-1/1540 cm-1, Figure 3B).”
Biophysical and Lipidomic Biomarkers of Cardiac Remodeling Post-Myocardial Infarction in Humans DOI: 10.3390/biom10111471
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