What absorbs at 3155 cm⁻¹ in an FTIR spectrum?
A band near 3155 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 |
|---|---|---|---|
| Water (H2O) | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Hydroxyl (O-H) confidence 1.0
“O-H O-H between the overtone of the bending band and the (cid:24)3155 cm-1 4+, asymmetric stretching band at from (F 2)-NH (cid:238) O-H stretching band in the difference spectra;”
Wei 等 - 2005 - Observation of the first hydration layer of isolat DOI: 10.1021/jp0453865 -
Water (H2O) confidence 1.0
“1 coordinated water, complex exhibited a wider absorption peak near 3155 The asymmetric cm-1 C(O)OC=O vibrational peaks near 1627 and 1587 show that the O atom in”
Cao 等 - 2020 - Synthesis and Effects of Two Novel Rare-Earth Ener DOI: 10.3390/ma13122811 -
Amide confidence 1.0
“For MP, the following vibration peaks are recognized, such as stretching vibration of -NH at 2 cm-1, cm-1, cm-1, 3+ 3393 stretching vibration of -NH at 3155 stretching vibration of C-N at 1671 and”
He 等 - 2019 - Novel Intumescent Flame Retardant Masterbatch Prep DOI: 10.3390/polym11010050
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