What absorbs at 775 cm⁻¹ in an FTIR spectrum?
A band near 775 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 775 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 |
| Amide | 3 | 3 | 1,0 |
| Aromatic ring | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Silicon (Si) | 2 | 1 | 1,0 |
| Thiocarbonyl | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| C n single bond | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 1,0 |
| Chlorine | 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 |
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 |
|---|---|---|---|
| silver nanoparticles | 775, 1636, 1631 | Alkyl C-H, Amide | 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 775 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
-
Acetate confiança 1,0
“TC-DO at 1412 and 779 W-DM had characteristic peaks at 1723 (C=O vibration), 1514, cm-1 corresponding to the characteristic peaks of TC-DM at 1643, 1465, 1413, 1456, 1422 and 775 cm-1.”
Discrimination and similarity evaluation of tissue-cultured and wild Dendrobium species using Fourier Transform Infrared Spectroscopy DOI: 10.1016/j.molstruc.2015.01.027 -
confiança 1,0
“6 FTIR spectra for a b c and of SPEs 16:2251-2260 2258 J Solid State Electrochem (2012) cm-1 8.0×10-8 cm-1 C-Cl functional group of stretching at 775 for aliphatS is obtained at 15% wt.”
Lee 等 - 2012 - Temperature dependence of the conductivity of plas DOI: 10.1007/s10008-011-1633-z -
Phosphate (PO4) confiança 1,0
“In the metaphosphate 775cm-1, (P-O-P) and (P-O-P) bands at about 900 and glass composition, CuO primarily acts as network modias s 43Q2 groups respectively, and the deformation modes of PO fier to depolymerize phosphate chain, until all the”
Shih 等 - 2003 - P-31 MAS-NMR and FTIR analyses on the structure of DOI: 10.1016/S0254-0584(03)00098-1 -
Alkene (C=C) confiança 1,0
“1624 Strong (methyne) 775 Medium Alkenyl C=C stretch Olefinic alkene 1458 Medium C=C-C aromatic ring stretch 775 Medium Alkenyl C=C stretch”
The Antimicrobial Activities of Silver Nanoparticles from Aqueous Extract of Grape Seeds against Pathogenic Bacteria and Fungi DOI: 10.3390/molecules26196081 -
Amide confiança 1,0
“The third (1239 and fourth cm-1) (775 amide band can be clearly seen only for PSi0, because in the PSi samples those bands are overlapped by the stronger aforementioned bands”
Thermal and surface properties of hybrid materials obtained from epoxy-functional urethane and siloxane DOI: 10.1007/s00289-015-1545-7 -
Acetate confiança 1,0
“(C-H 3308 stretching vibration), 2933 stretching of CH2 group), recorded in native nanocomposite components, were assigned corre- - O-H C-H 1602 (COOH stretching), 1429 (uronic acid (COOH)), 1018 825 sponding to stretching vibration at 3292”
Green decoration of graphene oxide Nano sheets with gelatin and gum Arabic for targeted delivery of doxorubicin DOI: 10.1016/j.btre.2022.e00722 -
Amide confiança 1,0
“a major peak has appeared at 775 These peaks were characteristic of C-N stretch (amines), =C-H bend (benzene, alkenes), and C-C (chlorides).”
Potential of Suaeda nudiflora and Suaeda fruticosa to Adapt to High Salinity Conditions DOI: 10.3390/horticulturae9010074 -
Thiocarbonyl confiança 1,0
“The following inference are made from the Cd2+, concentration of free as much of these ions would be in cm-1 found for pure observed FTIR results,The band at 775 42complex and most of the allylthiourea the form of CdCl Allylthiourea is assi”
Perumal 等 - 2023 - Influence of pH on the Growth of Tris-Allylthioure DOI: 10.14447/jnmes.v26i2.a07
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.