What absorbs at 1634 cm⁻¹ in an FTIR spectrum?
A band near 1634 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 | 9 | 8 | 1.0 |
| Carbonyl (C=O) | 5 | 5 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 0.9 |
| Alkene (C=C) | 4 | 4 | 0.9 |
| Water (H2O) | 3 | 3 | 0.9 |
| Protein beta sheet | 2 | 1 | 0.9 |
| N-O bond | 1 | 1 | 0.9 |
| Carboxyl (COOH) | 1 | 1 | 0.9 |
| Methacrylate | 1 | 1 | 0.9 |
| N h | 1 | 1 | 0.9 |
| C=n | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Carbonyl (C=O) confidence 1.0
“Explicit assignment: C=O stretching frequency at 1634 cm-1.”
Johnsirani 等 - 2013 - DOI: 10.4152/pea.201302095 -
confidence 1.0
“Explicit assignment: 'new peak at 1634 from carbonyl stretch of acyl group'”
Permadi 等 - 2020 - Synthesis and Characterization of Acylated Low Mol DOI: 10.17576/jsm-2020-4909-22 -
Amide confidence 1.0
“Explicit assignment: 'amide I (1634 cm-1)'”
Sun 等 - 2020 - Effects of SCCO2, Gamma Irradiation, and Sodium Do DOI: 10.3390/ijms21051565 -
Amide confidence 1.0
“Explicit assignment in text”
Wang 等 - 2014 - Electrospun polyurethane-core and gelatin-shell co DOI: 10.1088/1758-5082/6/1/015002. -
Alkene (C=C) confidence 0.9
“Distinct peak due to C=C.”
Ashri 等 - 2018 - Modified Dioscorea hispida starch-based hydrogels DOI: 10.1016/j.ijbiomac.2017.10.125 -
confidence 0.9
“Explicitly assigned to native protein structural elements.”
Hadnadev 等 - 2018 - Hempseed meal protein isolates prepared by differe DOI: 10.1016/j.foodhyd.2017.12.015 -
Protein beta sheet confidence 0.9
“Text attributes 1634 cm-1 to β-sheet structures.”
Ma 等 - 2001 - Study of oat globulin conformation by Fourier tran DOI: 10.1021/jf010053f -
N h confidence 0.9
“Explicit assignment: '1633.73cm-1 NeH'.”
Rajkumari 等 - 2019 - Synthesis of titanium oxide nanoparticles using Al DOI: 10.1016/j.jphotobiol.2019.111667
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