What absorbs at 683 cm⁻¹ in an FTIR spectrum?
A band near 683 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
Quick answer
A band near 683 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 |
|---|---|---|---|
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| N h | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
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 683 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
“The third intense band at 683 is assigned to the symmetric stretching of P-O-P Q2 Q1 cm-1 linkages in and structural unit [50].”
El-Hezzat 等 - 2021 - Structure - Properties study of Na2O-CaO-PbO-P2O5 DOI: 10.1016/j.solidstatesciences.2021.106666 -
confidence 1.0
“The highest-frequency A1g mode at 683 cm-1 is assigned to the symmetric stretching vibrations of the oxygen atoms with respect to the metal ion Coatings2023,13,1250 8of15 in the tetrahedral sites, a mode that can be also described as tetrah”
Synthesis of CoFe2O4 through Wet Ferritization Method Using an Aqueous Extract of Eucalyptus Leaves DOI: 10.3390/coatings13071250 -
Metal oxygen confidence 1.0
“cm-1 at ~615 shows the single degenerate symmetric vibrations of O-Cu-O linkages along with vibrations units.(73,76) in TeO After the annealing treatment, the 4 cm-1 sharp peak at 683 which corresponds to TeO 4”
Kaur 等 - 2020 - Structure of copper tellurite and borotellurite gl DOI: 10.13036/17533562.61.1.007 -
Carbonate confidence 1.0
“tion band at 683 was associated with carbonate”
Identification of pigments used in a Qajar manuscript from Iran by using atomic and molecular spectroscopy and technical photography methods DOI: 10.1186/s40494-022-00665-x -
C c single bond confidence 1.0
“The band appearing at 683 ± 2 1612 ± 1 cm-1 was assigned the C-C macrocycle ring deformation.”
Optical Absorption and Visible Photoluminescence from Thin Films of Silicon Phthalocyanine Derivatives DOI: 10.3390/ma7096585 -
confidence 0.9
“Explicit assignment: 'two bonds representing the α-phase of PA12 were observed at wavenumber of 576 and 683'”
Surface modification of the laser sintering standard powder polyamide 12 by plasma treatments DOI: 10.1002/ppap.201800032
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