What absorbs at 694 cm⁻¹ in an FTIR spectrum?
A band near 694 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 10 | 10 | 1.0 |
| Silicon (Si) | 7 | 7 | 1.0 |
| Alkyl C-H | 5 | 5 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Silicon-oxygen (Si-O) confidence 1.0
“gel-silica spectra already observed in the gel compound, the binary material (G 40s 60) present at t=0 min, bands at 1160, 796, 775 and (A) 694cm-1 assigned to quartz phase [23] due to the presence of crystallized silica in the mixture.”
Consolidation mechanism of materials obtained from sodium silicate solution and silica-based aggregates DOI: 10.1016/j.jnoncrysol.2011.04.006 -
Alkene (C=C) confidence 1.0
“The peaks around 840, 954, and 694 cm-1 are due to the bending vibration of =C-H groups.”
Innovative Investigation of Zinc Oxide Nanoparticles Used in Dentistry DOI: 10.3390/cryst12081063 -
Silanol (Si-OH) confidence 1.0
“Actually, [24,25],the deformation of Si-OH bond at Q2/Q3+Q4 870cm-1 694cm-1 an increase in the intensity ratio (Fig.”
Physico-chemistry of silica / Na silicate interactions during consolidation. Part 2: Effect of pH DOI: 10.1016/j.jnoncrysol.2011.11.005 -
Alkyl C-H confidence 1.0
“The peak observed at 694 cm Weight Element name corresponds to the CH out of plane deformations [39].”
Adeniyi 等 - 2022 - Evaluating the nature of captured exhaust soot fro DOI: 10.24200/sci.2021.57008.5017 -
confidence 1.0
“cm-1 cm-1 1,600.6 for the aromatic compounds (C-C stretch), 1,113.5 for aliphatic amines (C-N stretch), and cm-1 693.6 for alkyl halides (C-Cl stretch).”
Role of Salvinia molesta in biodecolorization of methyl orange dye from water DOI: 10.1038/s41598-020-70740-5 -
Silicon (Si) confidence 1.0
“smoothing function of two polynomials and 15 points, and finally normalized based on a reference cm-1 The band at 694 has been attributed to Si-O of SiO symmetrical bending, and its presence confirms the 4 quartz24,25.”
Spectroscopic investigations to reveal synergy between polystyrene waste and paraffin wax in super-hydrophobic sand DOI: 10.1038/s41598-023-36987-4 -
Silicon (Si) confidence 1.0
“cm-1 Moreover, the absorption band at 694 is corresponding to symmetrical bending vibrations of Si-O whereas cm-1 vibration band at 792 can be attributed to symmetrical stretching vibrations of Si-O [37].”
Magnetron sputtering technique for analyzing the influence of RF sputtering power on microstructural surface morphology of aluminum thin films deposited on SiO2/Si substrates DOI: 10.1007/s00339-021-04892-0 -
Ring structure confidence 1.0
“The cm-1, 1164, 1251, 1315, 1493, 1593, and 1651 being assigned to the following vibrational main IR bands of the SPCE-RGO/PDPA platform peak at 694, 750, 779, 881, 916, 970, 1014, modes: inter-ring deformation, ring deformation, W-O c-W (o”
Optical Evidence for the Assembly of Sensors Based on Reduced Graphene Oxide and Polydiphenylamine for the Detection of Epidermal Growth Factor Receptor DOI: 10.3390/coatings11020258
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