What absorbs at 1750 cm⁻¹ in an FTIR spectrum?
A band near 1750 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 |
|---|---|---|---|
| Carbonyl (C=O) | 26 | 25 | 1.0 |
| C-O single bond | 4 | 4 | 0.9 |
| Carboxyl (COOH) | 3 | 3 | 0.95 |
| Amide | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 0.9 |
| Lipid | 2 | 1 | 0.9 |
| Alkene (C=C) | 1 | 1 | 0.9 |
| Carbohydrate | 1 | 1 | 0.8 |
| Imide | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Amide confidence 1.0
“Assigned to amide I and C=O stretching.”
El-Sohaimy 等 - 2022 - Nutritional Quality, Chemical, and Functional Char DOI: 10.3390/plants11212825 -
confidence 1.0
“Carbonyl stretching of ester.”
Chiella Ruschel 等 - 2014 - EXPLORATORY ANALYSIS APPLIED TO ATTENUATED TOTAL R DOI: 10.5935/0100-4042.20140130 -
Carboxyl (COOH) confidence 0.95
“Explicit assignment: 'carboxylic groups were produced as shown by absorption peaks at 1750 cm-1'”
Chand 等 - 2009 - Chemical modification of carbonized wheat and barl DOI: 10.1016/j.jhazmat.2008.12.125 -
Carbonyl (C=O) confidence 0.9
“Explicit assignment: 1750 cm-1 (C=O ester).”
Hu 等 - 2011 - Influence of hydrolytic degradation on the surface DOI: 10.1016/j.polymdegradstab.2011.04.020 -
Carbonyl (C=O) confidence 0.9
“Text: 'appearing at 1750 cm-1 on the lactic acid'”
Lafia-Araga 等 - 2021 - Influence of Lactic Acid Surface Modification of C DOI: 10.3390/biom11091346 -
Carbonyl (C=O) confidence 0.9
“Stretching mode >C=O at 1750 attributed to acetylation.”
Olagunju 等 - 2020 - Influence of acetylation on physicochemical and mo DOI: 10.1016/j.foodhyd.2019.105424 -
confidence 0.9
“Text: 'C]O the ester, acid and ketone vibrations between 1750 cm-1'”
Ouyang 等 - 2006 - Improving the aging resistance of styrene-butadien DOI: 10.1016/j.polymdegradstab.2005.06.009 -
Amide confidence 0.9
“Text: 'Amide I and II region (from 1750 to 1480 cm-1)'”
Ali 等 - 2018 - A simple model for cell type recognition using 2D- DOI: 10.1016/j.molstruc.2018.03.044
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