What absorbs at 727 cm⁻¹ in an FTIR spectrum?
A band near 727 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 |
|---|---|---|---|
| Alkyl C-H | 3 | 3 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Carbonate | 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
“aromatic group in strong (C-H bend stretch, aliphatic amines group in medium (C-N stretch, 1055.96, 1038.12cm-1), alkenes group in strong (C-H rock, 981.81, 726.78cm-1), and alkyl halides group in medium (C-Br 567.83cm-1).”
Baranitharan 等 - 2022 - Fabrication of Silver Nanoparticles Using Fimbrist DOI: 10.1155/2022/4083663 -
Metal oxygen confidence 1.0
“856 0.47 0.59 Al-O stretching 727 0.5 0.6 653 0.5 0.6 Table 5: DRIFT bands that are characterizing coated and bonded”
El-Naggar - 2013 - Characterization of Modified and Polymer Coated Al DOI: 10.1155/2013/706960 -
Aromatic ring confidence 1.0
“Weaker bands at 727, 1022, and 1413 assigned to aromatic CH out of plane bending, aromatic CH in-plane”
Binational survey of personal protective equipment (PPE) pollution driven by the COVID-19 pandemic in coastal environments: Abundance, distribution, and analytical characterization DOI: 10.1016/j.jhazmat.2021.128070 -
Metal oxygen confidence 1.0
“LLM confirmed rule peak-group candidate”
Effect of aluminum fluoride complexation on fluoride removal by coagulation DOI: 10.1016/j.colsurfa.2011.12.010 -
Alkene (C=C) confidence 1.0
“The weak absorption peak at 727 belongs to the rocking double bonds.”
Characterization of the Materials and Techniques of Red Lacquer Painting of a Horizontal Plaque Inscribed by General Feng Yü-hsiang DOI: 10.3390/coatings13030583 -
Carbonate confidence 0.9
“Assigned to out-of-plane bending (ν4) of CO32-.”
Reyes 等 - 2021 - Kinetics of the Thermal Decomposition of Rhodochro DOI: 10.3390/min11010034 -
confidence 0.9
“in-plane bending vibration CO at 750 and 727”
Zhang 等 - 2019 - A Micro-Scale Investigation of the Adsorption of C DOI: 10.1007/s42461-019-00118-3
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