What absorbs at 635 cm⁻¹ in an FTIR spectrum?
A band near 635 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 635 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.
Mögliche Funktionsgruppenzuweisungen
| Funktionelle Gruppe | Unterstützende Fakten | Zitierte Quellen | Höchstes Vertrauen |
|---|---|---|---|
| Hydroxyl (O-H) | 4 | 3 | 1,0 |
| Chlorine | 2 | 2 | 1,0 |
| Water (H2O) | 2 | 2 | 1,0 |
| Metal oxygen | 2 | 2 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| Hydrogen bond | 1 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 0,9 |
| Fluorine (C-F) | 1 | 1 | 0,9 |
| Carbon bromine | 1 | 1 | 0,7 |
| Sulfur | 1 | 0 | 0,7 |
Das Ranking spiegelt die gesammelte Literatur Evidenz wider, nicht eine einzelne maßgebliche Regel. Bestätigen Sie immer anhand Ihres Probenkontexts.
Possible materials
| Material | Unterstützende Peaks | Overlapping groups | Zitierte Quellen |
|---|---|---|---|
| hydroxyapatite | 635, 1620, 1639 | 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 635 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.
Literatur hinter diesen Zuweisungen
-
Hydrogen bond Vertrauen 1,0
“elements are electronegative element capable of forming reaction on compound can be identified from the peak with (1) intramolecular hydrogen bonding with the hydrogen element from cm-1 which represented the stretching weak intensity at 635”
Synthesis of a novel 1,4‐bis[2‐(5‐thiophen‐2‐yl)‐1‐benzothiophene]‐2,5‐dioctyloxybenzene pentamer for creatinine detection. DOI: 10.1002/ajoc.202100374 -
Water (H2O) Vertrauen 1,0
“This decomposition process was intended The peak at 635 was due to the incorporation of CdO due to the removal of moisture, physisorbed and cheminto PVA matrix in the FTIR spectra.”
Synthesis, Structural, Optical, Electrical and Thermal Studies of Poly(vinyl alcohol)/CdO Nanocomposite Films DOI: 10.1007/s10904-017-0662-1 -
Metal oxygen Vertrauen 1,0
“Fe-O Stretching 635 Fe-O Stretching 510”
do Nascimento-Dias 等 - 2020 - Detection of organic or inorganic material in Mart DOI: 10.1017/S147355042000021X -
Vertrauen 1,0
“The Raman spectra of the nanocomposites at various Er2O3 concentrations are shown C-Cl bonds induced the strong peaks at 635 and in Figure 4.”
New Hybrid PVC/PVP Polymer Blend Modified with Er2O3 Nanoparticles for Optoelectronic Applications DOI: 10.3390/polym15030684 -
Hydroxyl (O-H) Vertrauen 1,0
“According to FTIR spectra, the stretching bands at 3571 cm-1, vibrations bands at 635 cm-1 originating from OH-groups, as well characteristic bands due to PO ions are clearly visible.”
Broda 等 - 2019 - Synthesis and selected physicochemical properties DOI: 10.5277/ppmp19073 -
Hydroxyl (O-H) Vertrauen 1,0
“The FTIR maxima present at around 635 cm-1 belongs to the that are observed in 3200-3600 spectral region are specific to the H-O-H bands of structural OH groups (stretching and vibrational modes).”
Development of Silver Doped Hydroxyapatite Thin Films for Biomedical Applications DOI: 10.3390/coatings12030341 -
Alkyl C-H Vertrauen 1,0
“cm-1 cm-1 FTIR spectra, typical absorption peaks were observed at 2,956 (C-H), 1720 (C=O), 1,635 cm-1 cm-1 (C=C), 1,250 (C-O-C), and 1,152 (C=O).”
JI-HYUN 等 - 2019 - Evaluation of physical property and cytotoxicity o DOI: 10.13065/jksdh.20190020 -
Vertrauen 1,0
“cm-1 The peak at 634.58 refers to the C-Cl stretching band of the halo compound.”
James 等 - 2022 - Synthesis and Characterization of Novel Nano-carbo DOI: 10.15376/biores.17.3.4452-4469
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