What absorbs at 641 cm⁻¹ in an FTIR spectrum?
A band near 641 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 3 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
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confidence 1.0
“3/2 1/2 species.1,3 According to the literature data peaks at 640.6 and 652.7 eV are ascribed to Mn(II) zeolites.32,33 On the other hand, bands at 642.0 and 654.7 eV are typical for Mn(III) species in”
Incorporation of Mn into the vacant T-atom sites of a BEA zeolite as isolated, mononuclear Mn: FTIR, XPS, EPR and DR UV-Vis studies DOI: 10.1039/c6cp01713d -
Hydroxyl (O-H) confidence 1.0
“The absorption at 641 hydroxyl bending within the layers.”
Nabipour 和 Sadr - 2015 - Layered zinc hydroxide-ibuprofen nanohybrids synt DOI: 10.1080/17458080.2014.998301 -
Acetate confidence 1.0
“The 1,641 cm-1 cm-1 shift of the C-O stretching vibration of the phenolic part of o-vanillin from 1,257 to 1,238 cm-1 also supports the coordination of phenolic oxygen atoms.”
Wang 等 - 2009 - Synthesis, Crystal Structure, and Kinetics of the DOI: 10.3390/molecules14072582
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