What absorbs at 739 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 739 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.

Mogelijke functionele-groeptoewijzingen

Ranglijst weerspiegelt cumulatief literatuurbewijs, niet één gezaghebbende regel. Bevestig altijd aan de hand van uw monsterecontext.

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 739 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.

Literatuur achter deze toewijzingen

• Alkyl C-H vertrouwen 1,0

  “Meanwhile, numerous strong bands 739 804 cm-1, cm-1, cm-1 863 898 and 1455 in DiaRoot suggested the stretching of C-H groups.”

  Assiry 等 - 2023 - Microstructural and Elemental Characterization of DOI: 10.3390/app13074517
• C c single bond vertrouwen 1,0

  “Meanwhile, the peak at assigned 781, 767, 772, 735, 739 cm-1 corresponded to the C-C stretching vibration of the benzene ring [19].”

  Modification of Hydroxypropyltrimethyl Ammonium Chitosan with Organic Acid: Synthesis, Characterization, and Antioxidant Activity DOI: 10.3390/polym12112460
• Alkyl C-H vertrouwen 1,0

  “As a result of this experiment, we has peaks at 739 769 and cm-1 differently observed colored areas in the reaction tube with 815 assigned to out-of-plane CH bending vibrations orange products accumulated in the region of higher tempertypic”

  Talyzin 等 - 2014 - Hydrogen-Driven Cage Unzipping of C-60 into Nano-G DOI: 10.1021/jp500377s
• Aromatic ring vertrouwen 1,0

  “Besides, the peaks at 1560 and 739 corresponded to stretching vibration of aromatic C=C to the successful modification that the molecular chain of HNH was grafted onto the surface of rGO.”

  One-Step Reduction and Surface Modification of Graphene Oxide by 3-Hydroxy-2-Naphthoic Acid Hydrazide and Its Polypropylene Nanocomposites DOI: 10.3390/nano7020025
• vertrouwen 0,8

  “Same as above.”

  Purification and Glutaraldehyde Activation Study on HCl-Doped PVA–PANI Copolymers with Different Aniline Concentrations DOI: 10.3390/molecules24010063