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.
Mogelijke functionele-groeptoewijzingen
| Functionele groep | Ondersteunende feiten | Geciteerde bronnen | Hoogste vertrouwen |
|---|---|---|---|
| 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 |
Ranglijst weerspiegelt cumulatief literatuurbewijs, niet één gezaghebbende regel. Bevestig altijd aan de hand van uw monsterecontext.
Possible materials
| Materiaal | Ondersteunende pieken | Overlapping groups | Geciteerde bronnen |
|---|---|---|---|
| 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.
Literatuur achter deze toewijzingen
-
vertrouwen 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 vertrouwen 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) vertrouwen 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 -
vertrouwen 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 vertrouwen 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 -
vertrouwen 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 vertrouwen 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) vertrouwen 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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