What absorbs at 785 cm⁻¹ in an FTIR spectrum?
A band near 785 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
Quick answer
A band near 785 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.
可能的官能团归属
| 官能团 | 支持性事实 | 引用来源 | 最高置信度 |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Nucleic acid | 2 | 2 | 1.0 |
| Silicon carbon | 2 | 1 | 1.0 |
| N h | 2 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
排名反映了累积的文献证据，而非单一的权威规则。请始终对照您的样品背景进行确认。
Possible materials
| 材料 | 支持峰 | Overlapping groups | 引用来源 |
|---|---|---|---|
| polypyrrole | 785, 1700, 400 | Alkyl C-H | 1 |
| TiO2 | 785, 1700, 1093 | Alkyl C-H | 1 |
| PPy | 785, 1043, 910 | Alkyl C-H | 1 |
| silicate | 785, 1000, 1037 | Silicon-oxygen (Si-O), Silicon (Si), Alkyl C-H | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 785 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
这些分配背后的文献
-
置信度 1.0
“At the wave number 785.05 cm-1 there is absorption band of Si-O-Al.”
Synthesis and catalytic activity of mesoporous Al-MCM-41/UiO-66 for esterification of oleic acid DOI: 10.1063/1.5082500 -
Nitrogen heterocycle 置信度 1.0
“belongs to s-triazine ring (C 3N 3) bending mode indicating The peak at 785”
Ramesh 等 - 2010 - Synthesis of Nano Structured Carbon Nitride by Pyr DOI: 10.1080/10584587.2010.489421 -
Alkene (C=C) 置信度 1.0
“found at 1230 which is due to C-O-C aliphatic ester cm-1 cm-1 stretching and peak of 810-760 band is at 785 FTIR spectroscopy for dosimetry which is due to =C-H bending [20].”
Sahoo 等 - 2020 - A new approach for high-dose measurement using CR- DOI: 10.1007/s10967-020-07232-3 -
置信度 1.0
“cm-1 cm-1 cm-1) ip 1260 (Si-CH stretching), doublet peak (1072 and 1007 (Si-O-Si 3 t 785cm-1 stretching) and (Si-CH wagging) (Fig.”
Bao 等 - 2018 - Manufacturing and characterization of long-acting DOI: 10.1016/j.ijpharm.2018.09.004. -
Alkyl C-H 置信度 1.0
“The cm-1 typical bands of PPy, at 1540/1550 (C-C stretching in pyrrole ring of PPy salt/base), cm-1 cm-1 1450 (C-N stretching in pyrrole ring), 1310 (C-H and C-N in-plane deformacm-1 cm-1 (N-H+ tions), 1170 (C-H and N-H in-plane deformation”
Polypyrrole Aerogels: Efficient Adsorbents of Cr(VI) Ions from Aqueous Solutions DOI: 10.3390/gels9070582 -
置信度 1.0
“ν(NS)δ(CCC) vibrational mode in both complexes”
Ni-thiosaccharinate complexes: synthesis, characterization and DFT studies. Biological properties as superoxide dismutase mimetics and as anti-carcinogenic agents DOI: 10.1016/j.ica.2019.04.040 -
N h 置信度 1.0
“cm1 The absorption band at 785 (figure 4a) corresponds to NH wagging [34].”
Interaction of (3-Aminopropyl)triethoxysilane With Late Ar-N 2 Afterglow: Application to Nanoparticles Synthesis DOI: 10.1002/ppap.201500201 -
Hydroxyl (O-H) 置信度 1.0
“As OTi bond, and the band at 785 to the As OH vibrations.”
Polymerization of silicate on TiO2 and its influence on arsenate adsorption: An ATR-FTIR study DOI: 10.1016/j.colsurfa.2015.01.021
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