What absorbs at 3632 cm⁻¹ in an FTIR spectrum?
A band near 3632 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
Quick answer
A band near 3632 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Hydroxyl (O-H) | 8 | 8 | 1.0 |
| Water (H2O) | 4 | 3 | 1.0 |
| Metal hydroxyl | 2 | 2 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Thiol | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| PVA | 3632, 1660, 2930 | Hydroxyl (O-H) | 1 |
| TiO2 | 3632, 1700, 1093 | Hydroxyl (O-H) | 1 |
| water | 3632, 1018, 2945 | Hydroxyl (O-H), Water (H2O) | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 3632 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Hydroxyl (O-H) confidence 1.0
“4 (a)] showed features spectrum band at 2946.67 1 cm-1 (stretching vibration of C-H from alkyl group), 1142.72 ( C-O stretching vibration, 1436.69 cm-1 cm-1 cm-1 (-CH 2stretching), 855.72 (C-C stretching) and the absorption band at 3631.72”
Sprayed in-situ synthesis of Polyvinyl alcohol/Chitosan loaded Silver nanocomposite hydrogel for improved antibacterial effects DOI: 10.1016/j.ijbiomac.2019.09.186 -
Hydroxyl (O-H) confidence 1.0
“The side peaks at 3632 and 3615 were clearly developing ment of the phenolic peak.”
Temperature dependent degradation of phenolic stabilizers and ageing behaviour of PP-R micro-specimen DOI: 10.1016/j.polymdegradstab.2023.110311 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Franca 等 - 2020 - Monitoring diclofenac adsorption by organophilic a DOI: 10.1016/j.envpol.2013.04.012 -
Water (H2O) confidence 1.0
“Water bands appear at 3632 (+), 3618”
Iwata 等 - 2009 - Identification of FTIR Bands Due to Internal Water DOI: 10.1021/bi801990s. -
confidence 1.0
“One group of untreated cells was considered as the cm-1 cm-1 peaks of 3632 and 2929 are related to the N-H control group.”
Preparation, characterization, and anticancer efficacy of novel cobalt oxide nanoparticles conjugated with thiosemicarbazide DOI: 10.1007/s13205-020-02230-4 -
Hydroxyl (O-H) confidence 1.0
“This spectrum Scientific), low-temperature chamber (Harrick evacuated to the lowest (3725cm-1, exhibits IR bands of surface hydroxyls of anatase (ca.<10-3mbar) stable pressure and kept under dynamic vacuum for 3632cm-1) (3680cm-1, 3414cm-1)”
Litke 等 - 2019 - Interfacial charge transfer in Pt-loaded TiO2 P25 DOI: 10.1016/j.jphotochem.2018.10.023 -
Hydroxyl (O-H) confidence 1.0
“The narrow bands at 3632 and 3418 which have a similar behaviour, are likely due to unperturbed ν(OH) modes of water at the borders of the patches.”
Mino 等 - 2012 - Particles Morphology and Surface Properties As Inv DOI: 10.1021/jp303942h -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Mino 等 - 2013 - Rutile Surface Properties Beyond the Single Crysta DOI: 10.1021/jp401916q
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