What absorbs at 782 cm⁻¹ in an FTIR spectrum?
A band near 782 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
Resposta rápida
A band near 782 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 |
|---|---|---|---|
| Silicon (Si) | 2 | 2 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| Metal hydroxyl | 2 | 1 | 1,0 |
| Metal oxygen | 2 | 1 | 1,0 |
| Chlorine | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Amine primary | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 0,8 |
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 |
|---|---|---|---|
| Polyester | 782, 1700, 1250 | Alkyl C-H | 1 |
| glycerol | 782, 1585, 1630 | Alkyl C-H | 1 |
| lipids | 782, 1735, 810 | Alkyl C-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 782 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
-
Alkyl C-H confiança 1,0
“D = (1) (cid:7)cos(cid:6) cm-1 cm-1 Finaly, the weak bands at 782.0 and 680.5 indicated the existence of the C-H out-of-plane bending”
Cobalt nanoparticle production using algal extract: A nanocarrier for antimicrobial potential DOI: 10.1166/mex.2023.2392 -
Silicon (Si) confiança 1,0
“are attributed to Si-O-Si bending vibrations, B-O Absorption spectra measure the absorbed energy of bending vibration, and M-O stretching vibrations (where M canbeFeorAl).Thebandat782cm-1isattributedtoSi-O-Si electrons when they jump from l”
Ahmad 等 - 2021 - Spectroscopic Analysis for Harnessing the Quality DOI: 10.1155/2021/6629640 -
confiança 1,0
“On cm-1 strong band at 782 is due to the N-H wag of a primary amine.”
Research on Misfiring Fault Diagnosis of Engine Based on Wavelet Analysis DOI: 10.25165/j.ijabe.20181105.3748 -
Metal oxygen confiança 1,0
“linkages.57 M-O M-OH with the help of and However, the peaks at 781.69 eV could be assigned to Co 2p3/ Co+2 2 at the tetrahedral sites of ions.”
Iqbal 等 - 2023 - Reduced Graphene Oxide-Modified Spinel Cobalt Ferr DOI: 10.1021/acsomega.2c06636 -
Alkyl C-H confiança 1,0
“The peak at 1143 corresponds to cm-1 aromatic C-H stretching and the band at 782 is due to the rocking of CH 2, both in phenolic compounds [58].”
Grape Seeds: Chromatographic Profile of Fatty Acids and Phenolic Compounds and Qualitative Analysis by FTIR-ATR Spectroscopy DOI: 10.3390/foods9010010 -
Water (H2O) confiança 1,0
“The blank sample also provided vibration bands at 782 cm-1 and 520 cm-1, which are assigned to the bending of water that differ only by their shape and intensity [30].”
Calcium Oxalate and Gallic Acid: Structural Characterization and Process Optimization toward Obtaining High Contents of Calcium Oxalate Monohydrate and Dihydrate DOI: 10.3390/cryst11080954 -
Acetate confiança 1,0
“- 806 819 823 carbohydrate structure and δ (C-H) ν 1248 1243 1248 1248 1246 (C-O) acid stretching 782 775 788 785 777 ν-stretching vibrations, δ-deformation vibrations, s-symmetric, as-asymmetric, st-strong, w1136 - 1134 1153 1148 ν”
Samborska 等 - 2018 - Membrane Processing in the Sustainable Production DOI: 10.3390/app8071082 -
Phosphate (PO4) confiança 1,0
“cm-1 cm-1 be identified at 1269 (P=O stretching vibration), 988 (P-O stretching vibration) cm-1 and 782 (P-O-C asymmetric stretching vibration) [27].”
Bio-Based Phosphate-Containing Polyester for Improvement of Fire Reaction in Wooden Particleboard DOI: 10.3390/polym15051093
Tem um espectro com esta banda?
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