What absorbs at 3572 cm⁻¹ in an FTIR spectrum?
A band near 3572 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 3572 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) | 16 | 16 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 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 |
|---|---|---|---|
| hydroxyapatite | 3572, 1620, 1639 | Phosphate (PO4), Hydroxyl (O-H), Carbonate | 2 |
| HAp | 3572, 917, 962 | Phosphate (PO4), Hydroxyl (O-H), Carbonate | 1 |
| Silver Nanoparticles | 3572, 1636, 1631 | Hydroxyl (O-H) | 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 3572 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
“LLM confirmed rule peak-group candidate”
Effect of calcination temperature on characterization of natural hydroxyapatite prepared from carp fish bones DOI: 10.1007/s42452-019-0396-5 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Permatasari 和 Yusuf - 2019 - Characteristics of Carbonated Hydroxyapatite Based DOI: 10.1088/1757-899X/546/4/042031 -
Hydroxyl (O-H) confidence 1.0
“631 Addition of SiO into biohydroxyapatite the change in the hydroxyl stretching bands at 3572”
Asmi 等 - 2016 - Synthesis and Characterisation of Composite based DOI: 10.1063/1.4945463 -
Hydroxyl (O-H) confidence 1.0
“The analysis of the IR spectrum of pure HAp starts from the sharp peak at 3572 cm-1 (Table 5), which is due to the stretching mode of the (OH)- group [54]: this characteristic peak can be considered the fingerprinting of the hydroxyapatite”
Structural Characterization of Low-Sr-Doped Hydroxyapatite Obtained by Solid-State Synthesis DOI: 10.3390/cryst13010117 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Baranitharan 等 - 2022 - Fabrication of Silver Nanoparticles Using Fimbrist DOI: 10.1155/2022/4083663 -
Metal oxygen confidence 1.0
“[36] 2987 s 2987 s 2987 s 2987 s 3675 m 3675 m 3675 m 3675 m O-H stretching HA (3572) [33] vw: very weak;”
Calcium phosphate powder synthesis by out-of-phase pulsed sonoelectrochemistry DOI: 10.1016/j.biomaterials.2009.07.002 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Demnati 等 - 2015 - Comparison of Physical-chemical and Mechanical Pro DOI: 10.1002/14356007.a06_399.pub2 -
Hydroxyl (O-H) confidence 1.0
“The bands at 632/3572 cm-1 43are assigned to liberational/str hing modes of hydroxyl groups and the bands near 3420 and 1635 cm-1 arise from the adsorbed water molecules [36].”
Engin 和 Girgin - 2009 - Synthesis of hydroxyapatite by using calcium carbo DOI: 10.2478/s11532-009-0063-6
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