What absorbs at 503 cm⁻¹ in an FTIR spectrum?
A band near 503 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 7 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“The band at 803 represented the stretching of C-H at 503 cm-1 was seen to be attributed to condensed octahedral AlO6 [18].”
Bekhoukh 等 - 2021 - Development, Investigation, and Comparative Study DOI: 10.3390/polym13193344 -
Acetate confidence 1.0
“Changes in C=O bands 503 in IR spectra were affected when the OM was heated with minerals.”
Hirakawa 等 - 2021 - Effects of minerals on metamorphism of organic mat DOI: 10.1016/0016-7037(89)90180-4 -
Water (H2O) confidence 1.0
“Increase in absorbability (A) and water absorption (WA), 503 synchronized with the increase in the viscosity of the mixture, the gas escapes to the outside.”
Liszkowska 等 - 2019 - The Effect of Accelerated Aging Conditions on the DOI: 10.3390/app9132663 -
Alkyl C-H confidence 1.0
“The small absorption peaks at 765.74, 698.23 and togram of condition (iv), exhibited peaks at retention time cm-1 503.42 12.4, 15.87 and 22.8 min which indicated that addition of were corresponding to CH deformations as well nanoparticles a”
Enhanced degradation of indeno(1,2,3-cd)pyrene using Candida tropicalis NN4 in presence of iron nanoparticles and produced biosurfactant: a statistical approach DOI: 10.1007/s13205-019-1623-x -
Carboxyl (COOH) confidence 1.0
“LLM confirmed rule peak-group candidate”
Priya 和 Azhagan - 2023 - Influence of succinic acid species on structural, DOI: 10.15251/DJNB.2023.181.55 -
Silicon-oxygen (Si-O) confidence 0.9
“Assigned to SiO4 vibration.”
Characterization of a calcium phospho-silicated apatite with iron oxide inclusions DOI: 10.1016/j.jcrysgro.2010.12.054 -
confidence 0.9
“Explicitly attributed to C-O-S coupled vibrations.”
Flotation Performance, Structure-Activity Relationship and Adsorption Mechanism of O-Isopropyl-N-Ethyl Thionocarbamate Collector for Elemental Sulfur in a High-Sulfur Residue DOI: 10.3390/met
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