What absorbs at 566 cm⁻¹ in an FTIR spectrum?
A band near 566 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 566 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 |
|---|---|---|---|
| Phosphate (PO4) | 9 | 9 | 1.0 |
| Metal oxygen | 3 | 3 | 1.0 |
| Phosphorus | 2 | 2 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 0.9 |
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 |
|---|---|---|---|
| calcium phosphate | 566, 1070, 1149 | Phosphate (PO4), Phosphorus | 1 |
| hydroxyapatite | 566, 1620, 1639 | Phosphate (PO4), Phosphorus | 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 566 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
-
Phosphate (PO4) confidence 1.0
“Finally, the P-O (H) group presents a band at 566 cm-1 Materials2019,12,2389”
Development of Composite Scaffolds Based on Cerium Doped-Hydroxyapatite and Natural Gums—Biological and Mechanical Properties DOI: 10.3390/ma12152389 -
Metal oxygen confidence 1.0
“and 417 [13, 14] A broad hump due to water H-O-H antisymmetric and octahedral Fe-O stretching band at 566 cm-1”
Synthesis and characterization of cobalt ferrite nanoparticles for hyperthermia treatment application DOI: 10.1063/1.5052096 -
Metal oxygen confidence 1.0
“The peak at 566 is confirming E g)n, 𝛼h𝜈 A(h𝜈 = - (4) the Zn-O stretching vibration [28-31].”
Microwave assisted CdO–ZnO–MgO nanocomposite and its photocatalytic and antibacterial studies DOI: 10.1007/s10854-018-9968-1 -
Phosphate (PO4) confidence 1.0
“Sobre o grupamento P-O(H), verificou-se cm-1 a presença de bandas em 566 e 470 correspondendo 28,96”
Santos 等 - 2019 - Desenvolvimento de biomaterial composto por hidrox DOI: 10.1590/0366-69132019653732441 -
confidence 1.0
“8 cm-1 cm-1, dual-band at 566 and 603 which is a characteristic of crystalline calcium phosphate in hydroxyapatite [1][42-44] appears after 1 day of immersion for 92S6 P123 (Figure 3.C) and 92S6 P123 Sil (Figure 3.D) and only after 15 days”
Study of the effect of ordered porosity and surface silanization on in vitro bioactivity of sol-gel-derived bioactive glasses DOI: 10.1016/j.mtcomm.2022.104992 -
Carbonate confidence 1.0
“Carbonates (calcareous soils) show (see Figure 7) strong absorption bands near 1400 encrusted areas, confirmed the presence of silico-aluminate minerals, unequivocally cm-1, cm-1 and 870 and we can observe a peak for coin 566 at 1392 due to”
From Collection or Archaeological Finds? A Non-Destructive Analytical Approach to Distinguish between Two Sets of Bronze Coins of the Roman Empire DOI: 10.3390/molecules28052382 -
Silicon (Si) confidence 1.0
“cm-1, The spectrum for CFA has major peaks located at 1047 and 566 which can be ascribed to The spectrum for CFA has major peaks located at 1047 and 566 cm-1, which can be ascribed to Si-O-”
Mpelane 等 - 2020 - Application of Novel C-TiO2-CFAPAN Photocatalytic DOI: 10.3390/catal10080909 -
Phosphate (PO4) confidence 1.0
“LLM confirmed rule peak-group candidate”
Predoi 等 - 2017 - Textural, Structural and Biological Evaluation of DOI: 10.3390/ma10030229
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