What absorbs at 729 cm⁻¹ in an FTIR spectrum?
A band near 729 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 729 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 | 4 | 4 | 1,0 |
| Carbonate | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Metal oxygen | 2 | 2 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Nucleic acid | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 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 |
| Alkene (C=C) | 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 |
|---|---|---|---|
| zeolite | 729, 1013, 1245 | Alkyl C-H, Silicon-oxygen (Si-O), N h | 1 |
| Ionic Liquids | 729, 938, 1040 | Alkyl C-H, Silicon-oxygen (Si-O) | 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 729 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
“The cm-1 obtained from the CH absorption band shown at 728.97 2 rocking of the amide chain of the as-spun and drawn ILconfined”
Dawelbeit 和 Yu - 2021 - Tentative Confinement of Ionic Liquids in Nylon 6 DOI: 10.1021/acsomega.0c04740 -
Metal oxygen confiança 1,0
“Two peaks observed at ~729 and ~854 cm-1 are due to the stretching vibration mode of Ce-O-Ce (Cerium -oxygen) with a lower”
Oxygen vacancies and F+ centre tailored room temperature ferromagnetic properties of CeO2 nanoparticles with Pr doping concentrations and annealing in hydrogen environment DOI: 10.1016/j.jallcom.2020.156079 -
Carbonate confiança 1,0
“cm(cid:2)1 cm(cid:2)1, 876 and 885 which are also consistent with the literature.30 cm(cid:2)1 The carbonate peaks at 729 of synthetic n”
Long 等 - 2012 - From synthetic to biogenic Mg-containing calcites DOI: 10.1039/c2cp22453d -
Acetate confiança 1,0
“reported in literature due to the incomplete decomposition of the products and two prominent cm-1 cm-1 peaks appeared at 795 (La-O) and 1316 (C-O) reveals the existence of the oxalate ion cm-1 cm-1 while in this research work these peaks ap”
Study of structural, optical and electrical properties of La3+ doped Mg0.25 Ni0.15 Cu0.25 Co0.35 Fe2-x Lax O4 spinel ferrites DOI: 10.1016/j.physb.2020.412565 -
Metal oxygen confiança 1,0
“(Si-O-Si and Al-O-Si) Symmetric stretching vibration 729 721 720 721 716 714 722 (Si-O-Si and Al-O-Si) Symmetric stretching vibration of Si-O-Si(Al) 795 796 795 795 794 793”
Bohacs 等 - 2017 - CONTROL OF NATURAL ZEOLITE PROPERTIES BY MECHANICA DOI: 10.1515/amm-2017-0216 -
Alkyl C-H confiança 1,0
“267 cm-1, vibrations of aromatic rings, bands at 1486 and 1469 associated with CH and CH 268 3 2 cm-1, deformations, respectively and a band at 729 related to (CH 2) in-phase rocking,”
Franca 等 - 2020 - Monitoring diclofenac adsorption by organophilic a DOI: 10.1016/j.envpol.2013.04.012 -
Nucleic acid confiança 1,0
“Similar changes, although less pronounced, can be seen in other nucleic acid bands at 785 and 729 cm-1.”
Kochan 等 - 2020 - Vibrational Spectroscopy as a Sensitive Probe for DOI: 10.3390/s20123452 -
Alkyl C-H confiança 1,0
“The chemical compoThe absorption band at 729.08 is attributed to the out of C-H N-H sition of the as-synthesized cationic surfactants (HBT, DBT and the plane bending for the aromatic structure.”
The synthesis and characterization of benzotriazole-based cationic surfactants and the evaluation of their corrosion inhibition efficiency on copper in seawater DOI: 10.1039/c9ra04461b
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.