What absorbs at 768 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 768 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.

可能的官能团归属

排名反映了累积的文献证据，而非单一的权威规则。请始终对照您的样品背景进行确认。

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 768 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.

这些分配背后的文献

• Phosphate (PO4) 置信度 1.0

  “cm-1 (ii) The peak at 768 is assigned to symmetric stretching vibrations of the P-O-P rings and possible sharing At high dose of irradiation, most of the IR spectral bands of (AlO show distinct decrease in their intensities and a prominent”

  Photoluminescence, optical and structural properties of Pr3+-doped fluorophosphate glasses and their induced defects by gamma irradiation DOI: 10.1007/s10854-018-9120-2
• Aromatic ring 置信度 1.0

  “The band at 768 was 3.18% regression attributed to the ortho-disubstituted phenyl group.”

  Attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR) for quantification of piroxicam in tablet dosage from as a green analytical method DOI: 10.1002/vjch.202000049
• 置信度 1.0

  “Explicit assignment in text”

  Novel Copper(II) Complexes with N4,S-Diallylisothiosemicarbazones as Potential Antibacterial/Anticancer Drugs DOI: 10.3390/inorganics11050195
• Hydroxyl (O-H) 置信度 1.0

  “The around 1600 cm-1 H-O-H bending were assigned to Si-Si and The former could be attributed to the bands at ν= 768 and 728 Al-Si stretching vibrations, respectively.”

  Nojiri 等 - 2013 - Structural change of alkali feldspar by ball milli DOI: 10.2465/jmps.121122
• Water (H2O) 置信度 1.0

  “cm-1 cm-1, both DFO-B applications, the increased maxima at 1637 and 3342 assigned to as the intensive agarose peaks at 1370cm-1, 1037 cm-1, 928 cm-1, 887 cm-1 and 768 cm-1 were hydroxyls, are probably due to the water absorbed during the a”

  Desferrioxamine B: Investigating the Efficacy of Hydrogels and Ethanol Gels for Removing Akaganeite and Maghemite from Dry Wooden Substrates DOI: 10.3390/f14020247
• 置信度 1.0

  “cm-1 cm-1 parameter in this study, we attempted to estimate those 768 (C-Cl stretch = alkyl halides) and 646 (- C:C-H: phytochemicals quantitatively in MEAIL.”

  Identification of food preservative, stress relief compounds by GC–MS and HR-LC/Q-TOF/MS; evaluation of antioxidant activity of Acalypha indica leaves methanolic extract (in vitro) and polyphenolic fraction (in vivo) DOI: 10.1007/s13197-017-2590-z)
• Metal oxygen 置信度 1.0

  “In Figure 7, the strong peak at 768 cm-1 is due to the W-O bond in the tetrahedral.”

  Electro-Oxidation of Metal Oxide-Fabricated Graphitic Carbon Nitride for Hydrogen Production via Water Splitting DOI: 10.3390/coatings12050548
• Alkyl C-H 置信度 0.9

  “Text: '768 cm-1 for C-H bending'.”

  Bromo-substituted blocked hexamethylene diisocyanate adduct: synthesis, characterization and applica DOI: 10.1080/10601325.2020.1845569