What absorbs at 3621 cm⁻¹ in an FTIR spectrum?
A band near 3621 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 6 cited sources
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Hydroxyl (O-H) | 4 | 3 | 1.0 |
| Aromatic ring | 2 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Chitosan confidence 1.0
“FTIR spectrum presented significant peaks at 3621 1013 was attributed to chitosan, Accepted: 11October2022 cm-1 29Si, 27Al, 13H and 787 signified the stretching of Si-O-Si on HNT.”
Synthesis and Optimization of Superhydrophilic-Superoleophobic Chitosan–Silica/HNT Nanocomposite Coating for Oil–Water Separation Using Response Surface Methodology DOI: 10.3390/nano12203673 -
Aromatic ring confidence 1.0
“from alum and wood, aromatic skeletal vibration attribcalcium hydroxide at 3621 cm-1 uted to lignin at 1505”
Nanotechnologies for the restoration of alum-treated archaeological wood DOI: 10.1007/s00339-016-9833-0 -
Hydroxyl (O-H) confidence 1.0
“Sci.2021,11,10049 6of19 at 3696 and 3621 cm-1 (outer and inner hydroxyl ion bands), 1028 cm-1 (Si-O-Si band), and 914 cm-1 (Al-O-H band).”
Investigation of Ancient Wall Painting Fragments Discovered in the Roman Baths from Alburnus Maior by Complementary Non-Destructive Techniques DOI: 10.3390/app112110049 -
Hydroxyl (O-H) confidence 1.0
“Silver strongly diluted Deacon Both OH bands at 3621 and cm(cid:2)1 is resistant to dry and moist chlorine at room temperature.”
Farra 等 - 2013 - Understanding CeO2 as a Deacon catalyst by probe m DOI: 10.1039/C2CP42767B -
Water (H2O) confidence 1.0
“Since protein9cm-1 3621cm-1 induced FTIR were 6 and bound water molecules play important role in membrane for the 3633 and proteins action, observation of hydrogen-bonding alterations bands (Fig.”
Fukuda 等 - 2013 - Detection of a protein-bound water vibration of ha DOI: 10.2142/biophysics.9.167 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Ma 等 - 2019 - Investigation of the Optical, Physical, and Chemic DOI: 10.3390/su11143803
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