What absorbs at 774 cm⁻¹ in an FTIR spectrum?
A band near 774 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 774 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 |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Water (H2O) | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 0,9 |
A classificação reflete a evidência acumulada da literatura, não uma única regra autoritária. Sempre confirme com o contexto da sua amostra.
Possible materials
| Material | Picos de suporte | Overlapping groups | Fontes citadas |
|---|---|---|---|
| PVA | 774, 1660, 2930 | Hydroxyl (O-H) | 1 |
| ZnO | 774, 1400, 3430 | Hydroxyl (O-H) | 1 |
| CuO | 774, 453, 1000 | Hydroxyl (O-H) | 1 |
| glucose | 774, 1740, 1400 | Hydroxyl (O-H) | 1 |
| magnetite | 774, 1740, 1263 | Hydroxyl (O-H), Silicon-oxygen (Si-O) | 1 |
| quartz | 774, 800, 3053 | Silicon-oxygen (Si-O), Hydroxyl (O-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 774 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.
Literatura por trás destas atribuições
-
confiança 1,0
“cm-1 (ii) The peak at 774 can be attributed to 10 Zn (Glass) 3.8 3.6 3.5 symmetric stretching vibrations of P - O - P 10 Zn (comp) 5.1 5.1”
Helmy 等 - 2021 - Preparation and Characterization of some Composite DOI: 10.21608/EJCHEM.2021.80482.3986 -
Aromatic ring confiança 1,0
“The absorption peaks at 774 are assigned to aromatic C-H vibrations, indicating there are some aromatics with alkyl cm(cid:3)1 cm(cid:3)1 Transmittance substitution [21].”
Gradient separation of ⩾300°C distillate from low-temperature coal tar based on formaldehyde reactions DOI: 10.1016/j.fuel.2015.07.029 -
Water (H2O) confiança 1,0
“The only exception is that the absorbing band belonging to 774 h in PA11-RH had a 39% increase in curve area, which might be due to the reversible reaction of water with amide”
Comparative Characterization of Hot-Pressed Polyamide 11 and 12: Mechanical, Thermal and Durability Properties DOI: 10.3390/polym13203553 -
confiança 1,0
“cm-1 1710-1730 corresponds to the stretching vibrations of carbonyl groups (C=O), while the peaks corresponds to the stretching vibrations of carbonyl groups (C=O), while the peaks at 1534 and 774 cm-1 at 1534 and 774 correspond to the bend”
Synthesis of Linseed Oil-Based Waterborne Urethane Oil Wood Coatings DOI: 10.3390/polym10111235 -
Silicon-oxygen (Si-O) confiança 1,0
“The studied quartz was detected with bands at 460.90 cm-1, 491.73 cm-1, 773.68 cm-1, and 1071.43 cm-1.”
Fawzy - 2021 - Separation of fine beryl from quartz via magnetic DOI: 10.37190/ppmp/132329 -
C c single bond confiança 1,0
“829 C-C stretching 774 774 OH deformation 771”
Gallegos-Loya 等 - 2012 - An Optical Overview of Poly[mu(2)-L-alanine-mu(3)- DOI: 10.1100/2012/620189 -
confiança 0,9
“Text: '774 cm-1 (P G1)' for glucose”
Landari 等 - 2018 - Pseudo-Continuous Flow FTIR System for Glucose, Fr DOI: 10.3390/mi9100517 -
Siloxane (Si-O-Si) confiança 0,9
“explicit assignment in text”
Evaluation of polyvinyl alcohol–borax/agarose (PVA–B/AG) blend hydrogels for removal of deteriorated consolidants from ancient Egyptian wall paintings DOI: 10.1186/s40494-019-0264-z
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