What absorbs at 791 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 791 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。

Possible materials

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 791 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

• 置信度 1.0

  “showed the characteristic vibration of SiC at 791 Peaks cm-1 Si-O-Si Opositioned at 473 and 1102 were assigned to and 2.4.”

  In situ formation of β-silicon carbide nanorods from the hybrid of an organic moiety and methyltriethoxysilane DOI: 10.1016/j.matlet.2011.04.040
• Alkyl C-H 置信度 1.0

  “The absorption peak at 791 is characpyrimidine ring, and the stretching and swinging of the C H and cm-1 terized by the collective vibrations of four molecules in the lattice, H bonds.”

  A comparative study on the experimental and calculated results of mid-infrared and Raman vibrational modes of nucleic acid bases DOI: 10.1016/j.jmgm.2017.04.016
• Silicon carbon 置信度 1.0

  “cmthe bending CH3 groups originating from Si-CH3 bond, Si-O-Si groups (1089-1015 weight - 60.10, vapor density - 2.1 (vs air), vapor pressure - 33 mmHg (20°C) and 44 (791cm-1) 1) and the stretch Si-C bonds from CH3 in the case of ZnO/PDMS p”

  Sonmez 等 - 2018 - IDENTIFYING THE OPTIMUM METHOD FOR MODIFYING THE Z DOI: 10.1016/j.apcata.2012.03.037.
• Ring structure 置信度 1.0

  “Borate ring deformation (662 1), cm-1), BO bending (791 stretching vibration of 3”

  Vasumathy 等 - 2016 - Preparation and Characterization of the Structural DOI: 10.1590/1980-5373-MR-2016-0014
• Silicon carbon 置信度 0.9

  “Explicit assignment: characteristic vibration of SiC at 791 cm-1.”

  Growth of silicon carbide nanorods from the hybrid of lignin and polysiloxane using sol-gel process and polymer blend technique DOI: 10.1016/j.matlet.2009.08.029
• Siloxane (Si-O-Si) 置信度 0.9

  “explicit assignment in text”

  Evaluation of polyvinyl alcohol–borax/agarose (PVA–B/AG) blend hydrogels for removal of deteriorated consolidants from ancient Egyptian wall paintings DOI: 10.1186/s40494-019-0264-z
• 置信度 0.7

  “out-of-plane polymers”

  The effect of chain extender structure on the properties of new thermoplastic poly(carbonate–urethane)s derived from MDI DOI: 10.1007/s10973-016-5756-4