What absorbs at 3120 cm⁻¹ in an FTIR spectrum?
A band near 3120 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 7 cited sources
Resposta rápida
A band near 3120 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 3 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Carbonyl (C=O) | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Materiais possíveis
| Material | Picos de suporte | Grupos sobrepostos | Fontes citadas |
|---|---|---|---|
| polyurethane | 3120, 2270, 1700 | Alkyl C-H, Methacrylate, N h | 1 |
| polysaccharide | 3120, 1637, 1320 | Methacrylate, Hydroxyl (O-H), Alkyl C-H | 1 |
| PANI | 3120, 2930, 1300 | Alkyl C-H, N h | 1 |
Os materiais são mostrados apenas quando o mesmo conjunto de literatura suporta esta banda e pelo menos um pico característico adicional.
Lógica do espectro
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 3120 cm⁻¹ is usually not enough for material identification by itself.
Uso no mundo real
Este tipo de consulta é comum em identificação de polímeros, triagem de plásticos desconhecidos, solução de problemas de CQ, verificação de materiais reciclados e revisão de atribuição de picos apoiada pela literatura.
Erros comuns
- Tratar uma banda isolada como prova de um material sem verificar pelo menos um ou dois picos de suporte.
- Ignorando sobreposição: vários grupos funcionais podem contribuir próximo ao mesmo número de onda.
- Ignorar a validação quando aditivos, misturas, oxidação ou contaminação podem distorcer o espectro.
Conselho de verificação
Quando a ambiguidade persistir, valide a hipótese com DSC, GC-MS ou TGA, especialmente para misturas, amostras degradadas e polímeros carregados.
Literatura por trás destas atribuições
-
Secondary amine confiança 1,0
“The N-H) of the thioamide and amide can be observed at asymmetric stretching vibration of the secondary amine (ν 3177cm-1 3120cm-1 and respectively.”
Adan 等 - 2014 - Synthesis, Characterization and Antibacterial Stud DOI: 10.1063/1.4895199 -
Hydroxyl (O-H) confiança 1,0
“The vibrational bands at between between 3680 cm-1 and 3120 cm-1 are due to O-H and N-H stretching and can be attributed to cm-1 cm-1 between 3680 cm-1 and 3120 cm-1 are due to O-H and N-H stretching and can be attributed to 3680 and 3120 a”
Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft- Polyurethane Composites DOI: 10.3390/polym11010041 -
Hydroxyl (O-H) confiança 1,0
“cm(cid:3)1 3000-3550 467 In the range, a strong and wide -OH absorption band can be seen, which corresponds to stretchingvibrations.Thepeaksat3120and2980cm(cid:3)1thatcan be observed in Fig.”
Synthesis and characterization of a novel ruthenium(ii) trisbipyridine complex magnetic nanocomposite for the selective oxidation of phenols DOI: 10.1039/c9ra05079e -
Acetate confiança 1,0
“The asymmetric and symmetric stretching CH3 C=O stretching of CH group and band vibrations were found at 3120 and 1670-1665 3”
Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (FTIR) and Artificial Neural Networks Applied to Investigate Quantitative Changes of Selected Soluble Biomarkers, Correlated with H. pylori Infection in Children and Presumable Consequent Delayed Growth DOI: 10.3390/jcm9123852 -
Alkyl C-H confiança 1,0
“LLM confirmed rule peak-group candidate”
Mucilage from Yellow Pitahaya (Selenicereus megalanthus)Fruit Peel: Extraction, Proximal Analysis, and Molecular Characterization DOI: 10.3390/molecules28020786 -
confiança 1,0
“The 3409cm-1 3120cm-1 1614cm-1 the peaks at peak at and are attributed to Nrepresents the N-H bend vibration.”
Zhu 等 - 2013 - Electrochemical Properties of PANI as Single Elect DOI: 10.1155/2013/940153 -
confiança 0,8
“Observed band assigned to C-H.”
Density Functional Theory and Molecular Docking Investigations of the Chemical and Antibacterial Activities for 1-(4-Hydroxyphenyl)-3-phenylprop-2-en-1-one DOI: 10.3390/molecules26123631
Tem um espectro com esta banda?
Carregue seu espectro FTIR e obtenha um relatório de interpretação completo — atribuições de picos com citações da literatura, correspondências de biblioteca e uma cadeia de evidências com nível de confiança — em segundos.