What absorbs at 571 cm⁻¹ in an FTIR spectrum?
A band near 571 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 571 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 |
|---|---|---|---|
| Phosphorus | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ring structure | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| apatite | 571, 3053, 1640 | Phosphate (PO4), Phosphorus, Alkyl C-H | 1 |
| hydroxyapatite | 571, 1620, 1639 | Phosphate (PO4), Alkyl C-H, Phosphorus | 1 |
| chitosan | 571, 1650, 1655 | Alkyl C-H | 1 |
| Fe3O4 | 571, 2358, 1673 | Alkyl C-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 571 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
-
Aromatic ring confidence 1.0
“in SSSAJ: Volume 75: Number 2 • March-April 2011 571 cm-1 1238 could be due to aromatic-CH in plane deformation Particulate OM makes up 5 to 23% of the SOC, with the and has high partial least squares regression loadings for TOC smaller pro”
Calderon 等 - 2011 - Chemical Differences in Soil Organic Matter Fracti DOI: 10.2136/sssaj2009.0375 -
Silanol (Si-OH) confidence 1.0
“Series: Materials Science and Engineering (2017) 012047 doi:10.1088/1757-899X/202/1/012047 cm-1 cm-1 Si-Fe-O at 570.93 [6, 17], Si-OH stretching at 779.24 [11], and Si-O-Si stretching cm-1 asymmetric at 1049.28 [6, 15] clearly show the pres”
Deswardani 等 - 2017 - Study of Structural and Magnetic Properties of Sil DOI: 10.1088/1757-899X/202/1/012047 -
confidence 1.0
“Further, FT-IR spectroscopy reveals for Fe 3O a band at 571 which shows 4 4 theFe-Ostretchingmodeoftetrahedralandoctahedralsites.Formationofγ-Fe 2O 3uponannealingwasagainconfirmedfromthe cm-1 cm-1 cm-1.”
Yadav 等 - 2020 - Facile Synthesis of Substantially Magnetic Hollow DOI: 10.1007/s10948-020-05481-7 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Development of New Amphiphilic Catalytic Steam Additives for Hydrothermal Enhanced Oil Recovery Techniques DOI: 10.3390/catal12080921 -
Phosphate (PO4) confidence 1.0
“One strong and relatively broad band at 1062.78cm-1, two relatively strong and sharp bands at 570.95cm-1 603.71cm-1, and and another band at ABC 956.69cm-1 have appeared due to the presence of the 43-) phosphate (PO group of HAp.”
Malla 等 - 2020 - Extraction and Characterization of Novel Natural H DOI: 10.1155/2020/1690178 -
Phosphate (PO4) confidence 1.0
“The peaks cm-1 at 571, 604, 983, 1035, and 1098 are associated with the vibrational modes of the phosphate groups.”
Composition and content analysis of fluoride in inorganic salts of the integument of Antarctic krill (Euphausia superba) DOI: 10.1038/s41598-019-44337-6 -
confidence 0.9
“Explicit assignment in text.”
Spectral characterization of hydroxyapatite extracted from Black Sumatra and Fighting cock bone samples: A comparative analysis DOI: 10.1016/j.sjbs.2020.11.020 -
confidence 0.8
“Text: 'KBR absorption peak used as pellets'.”
Zam 等 - 2021 - Identification of chitosan beads from coconut crab DOI: 10.1088/1742-6596/1832/1/012014
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