What absorbs at 1779 cm⁻¹ in an FTIR spectrum?
A band near 1779 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 5 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Carbonyl (C=O) | 5 | 5 | 1.0 |
| Imide | 2 | 2 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Alkyl C-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
-
Imide confidence 1.0
“the unaged CBR 320/328 composites reveal three imide carbonyl peaks at 1779, 1728 and 1712 These peaks may be assigned to the symmetric and asymmetric stretches of an unsaturated imide (1779 and 1728 cm(cid:2)1)”
Fox 等 - 2004 - Investigation of failure mechanisms in aged aerosp DOI: 10.1016/j.engfailanal.2003.05.010 -
Carbonyl (C=O) confidence 1.0
“Fourier Transt Copyright: American Scientific Publishers cm-1, form Infrared Spectroscopy (FTIR) spectra shows two new absorbance peaks at 1779 and 1851 which i Delivered by Ingenta c correspond to symmetrical and asymmetrical stretching vi”
Compatibilization effect of EVA-g-MAH on mechanical, morphological and rheological properties of recycled PC/ABS blend DOI: 10.1166/mex.2014.1198 -
Alkyl C-H confidence 1.0
“Peaks that can only be assigned to polyimide in the blend include the methyl group C-H stretching cm-1), cm-1), C=O (symmetric stretching) (1779 C=O (anti-symetric stretching) (2957-2863 cm-1),”
Maab 等 - 2009 - SPEEKPolyimide Blends for Proton Conductive Membr DOI: 10.1002/fuce.200800121 -
Carbonyl (C=O) confidence 1.0
“In the FTIR cm(cid:3)1 spectrum strong absorption bands appeared at 1779 due to the asymmetric vibration of the carbonyl imide ring, at 1719 cm(cid:3)1 attributed to the symmetric vibration of carbonyl imide”
Serbezeanu 等 - 2016 - Phosphorus-containing polyimide fibers and their t DOI: 10.1039/c6ra06497c -
Carbonyl (C=O) confidence 0.95
“Explicit assignment: 'the C=O (of SMA) peak at a wavelength of 1779'”
The effect of Styrene Maleic Anhydride on the microstructure evolution of PSF-based membrane prepared by thermal-induced phase separation method DOI: 10.1016/j.mtcomm.2019.100687
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a confidence-rated evidence chain — in seconds.
Interpret my spectrum