What absorbs at 1500 cm⁻¹ in an FTIR spectrum?
A band near 1500 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 |
|---|---|---|---|
| Amide | 13 | 11 | 0.9 |
| Aromatic ring | 8 | 6 | 1.0 |
| Alkyl C-H | 5 | 5 | 0.9 |
| Carboxyl (COOH) | 5 | 3 | 0.9 |
| Alkene (C=C) | 4 | 4 | 0.95 |
| N h | 3 | 3 | 0.9 |
| C n single bond | 3 | 3 | 0.9 |
| Carbonate | 3 | 2 | 0.95 |
| Lignin | 3 | 2 | 0.8 |
| Hydroxyl (O-H) | 3 | 2 | 0.8 |
| C-O single bond | 2 | 2 | 0.8 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 0.9 |
| Methyl | 1 | 1 | 0.9 |
| Silanol (Si-OH) | 1 | 1 | 0.9 |
| C c single bond | 1 | 1 | 0.8 |
| Protein | 1 | 1 | 0.7 |
| Nucleic acid | 1 | 1 | 0.7 |
| Phospholipid | 1 | 1 | 0.7 |
| Phosphate (PO4) | 1 | 1 | 0.7 |
| Hydrogen bond | 1 | 1 | 0.7 |
| N eq o | 1 | 1 | 0.7 |
| Nitro (NO2) | 1 | 1 | 0.6 |
| Carbohydrate | 1 | 0 | 0.5 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
confidence 1.0
“explicit assignment”
Purhanudin 和 Awang - 2016 - Formation of chemical bonds and morphological stud DOI: 10.1063/1.4966804 -
Carbonyl (C=O) confidence 1.0
“Text: 'absorbance peak band at 1500 was resolved ... groups such as carbonyl and aromatic C=C'”
Wang 等 - 2021 - Surface Chemical Heterogeneity of Low Rank Coal Ch DOI: 10.3390/min11030239 -
Carbonate confidence 0.95
“Explicit assignment in text.”
Tacker - 2008 - Carbonate in igneous and metamorphic fluorapatite DOI: 10.2138/am.2008.2551 -
Alkene (C=C) confidence 0.95
“Explicit assignment: 'C=C' at 1500 cm-1.”
Ngo 等 - 2020 - Improvement of Hydrophilicity for Polyamide Compos DOI: 10.1155/2020/6641225 -
Aromatic ring confidence 0.9
“Text: 'peak at around 1500' and 'vibrations involving the aromatic ring'.”
Fox 等 - 2004 - Investigation of failure mechanisms in aged aerosp DOI: 10.1016/j.engfailanal.2003.05.010 -
Silanol (Si-OH) confidence 0.9
“Text states peak at 1500 corresponds to formation of silanol.”
Nandi 等 - 2019 - Performance of Composite Insulators Used for Elect DOI: 10.1007/s11665-019-04341-3 -
Carboxyl (COOH) confidence 0.9
“Text: 'absorption peaks at ... 1500 ... correspond to ... carboxylate ion (COO)'”
Shah 等 - 2016 - In-vitro digestibility, rheology, structure, and f DOI: 10.1016/j.foodchem.2016.06.019 -
Aromatic ring confidence 0.9
“Text: 'benzene peak at about 1500 cm-1'.”
da Silva 等 - 2015 - Infrared spectroscopy, nano-mechanical properties, DOI: 10.2319/070314-472.1
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