What absorbs at 857 cm⁻¹ in an FTIR spectrum?
A band near 857 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 857 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 |
|---|---|---|---|
| Metal oxygen | 2 | 2 | 1,0 |
| Sulfate (SO4) | 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 |
| Carbohydrate | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Silicon carbon | 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 |
|---|---|---|---|
| lignin | 857, 1035, 1510 | Methacrylate, Methoxy (OCH3) | 2 |
| cellulose | 857, 1735, 1650 | Methacrylate, Methoxy (OCH3) | 1 |
| hemicelluloses | 857, 1735, 1270 | Methacrylate, Methoxy (OCH3) | 1 |
| silica | 857, 1100, 1080 | Methacrylate | 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 857 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
-
Silicon carbon confiança 1,0
“LLM confirmed rule peak-group candidate”
Mhaisagar 等 - 2014 - Mechanical properties of surface modified silica l DOI: 10.1016/j.mee.2013.10.006 -
Metal oxygen confiança 1,0
“The absorption band at 953 and is designated to the stretching 857cm-1 frequency of Sr-O bond and Si-O stretching frequency appears at in the prepared silicate materials is due to the asymmetric 969cm-1 stretching frequency of Si-O bond in”
Down-conversion characteristics of Eu3+ doped M2Y2Si2O9 (M = Ba, Ca, Mg and Sr) nanomaterials for innovative solar panels DOI: 10.1016/j.pnsc.2019.07.003 -
confiança 1,0
“10 mA In the Ni 2p region, the peaks at 857.2 eV and 875.0 eV were assigned to Ni 2p3/2 and Ni 2p1/2, and the peaks at 862.5 eV and 880.4 eV 2.5.”
Ni(II)/Ni(III) redox couple endows Ni foam-supported Ni2P with excellent capability for direct ammonia oxidation DOI: 10.1016/j.cej.2020.126795 -
C c single bond confiança 1,0
“C-C polysaccharides, for instance, glycosaminoglycans, more specifically identify the stretching mode of proline at 857 and ~931”
Organic biopolymers of venus clams: Collagen-related matrix in the bivalve shells with crossed-lamellar ultrastructure DOI: 10.1016/j.bbrep.2021.100939 -
Metal oxygen confiança 1,0
“LLM confirmed rule peak-group candidate”
Gao 等 - 2013 - Effect of silicic acid on arsenate and arsenite re DOI: 10.1016/j.apgeochem.2013.09.005. -
Alkyl C-H confiança 1,0
“corresponding to aliphatic and aromatic -OH (3415 cm-1), aromatic ring modes (1595 cm-1 and 1140 cm-1), carbonyl group (1684 cm-1), aliphatic -CH3 (2944 cm-1) and CH2 groups (1453 cm-1), symmetric -CH3 stretching of the methoxyl groups (285”
Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures DOI: 10.3390/ma14113024 -
Water (H2O) confiança 1,0
“at 860.9 for and at 849.6 for When proton acceptor (PA) molecules of the water dimer at 3590.5 wateriscodepositedwithOCS,weattributethebandsat857.2 cm(cid:12) 1, and 3660.6 respectively, and these bands are attributed cm(cid:12)”
First infrared investigations of OCS–H 2 O, OCS–(H 2 O) 2 , and (OCS) 2 –H 2 O complexes isolated in solid neon: Highlighting the presence of two isomers for OCS–H 2 O DOI: 10.1063/1.4986403 -
Carbohydrate confiança 1,0
“(Kotwaliwale et al., agriculture and food quality evaluation cm-1 the 857 band, assigned to pectin (Synytsya et al., 2003).”
From the Soft to the Hard: Changes in Microchemistry During Cell Wall Maturation of Walnut Shells DOI: 10.3389/fpls.2020.00466
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