What absorbs at 790 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 790 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

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

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 790 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

• Aromatic ring

  Reported band

  790 cm-1

  Assignment

  Aromatic ring

  Material / context

  PANI-ECMA composites

  Synthesis of novel conducting polyaniline composites based on seaweed Enteromorpha compressa macro-alga powder DOI: 10.1007/s00289-020-03191-7
• Carboxyl (COOH)

  Reported band

  790 cm-1

  Assignment

  Carboxyl (COOH)

  Material / context

  acid leached palygorskites; acid leached palygorskite; Mg-poor palygorskite

  A Fourier transform infrared spectroscopic study of Mg-rich, Mg-poor and acid leached palygorskites DOI: 10.1016/j.saa.2006.02.053
• Metal oxygen

  Reported band

  790 cm-1

  Assignment

  Metal oxygen

  Material / context

  ferric arsenic-containing colloid; gypsum

  ATR-FTIR spectroscopic characterization of ferric arsenic-containing colloid and gypsum DOI: 10.5004/dwt.2019.23721
• C c single bond

  Reported band

  790 cm-1

  Assignment

  C c single bond

  Material / context

  Bacillus megaterium; AgNPs

  Microorganism-mediated green synthesis of silver nanoparticles using Aspergillus niger and Bacillus megaterium DOI: 10.15251/DJNB.2022.171.359
• Silicon carbon

  Reported band

  790 cm-1

  Assignment

  Silicon carbon

  Material / context

  silica aerogels; silica aerogels from TMOS/MTMS mixtures

  Physico-chemical properties of silica aerogels prepared from TMOS/MTMS mixtures DOI: 10.1007/s10934-010-9410-4
• Amide

  Reported band

  790 cm-1

  Assignment

  Amide

  Material / context

  —

  Lousicidal activity of synthesized silver nanoparticles using Lawsonia inermis leaf aqueous extract against Pediculus humanus capitis and Bovicola ovis DOI: 10.1007/s00436-011-2667-y
• Alkyl C-H

  Reported band

  790 cm-1

  Assignment

  Alkyl C-H

  Material / context

  1,5-methylnaphthalene

  FTIR and FT Raman, molecular geometry, vibrational assignments, ab initio and density functional theory calculations for 1,5-methylnaphthalene DOI: 10.1016/j.saa.2010.09.002