What absorbs at 2923 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2923 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 2923 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

• Alkyl C-H

  Reported band

  2923 cm-1

  Assignment

  Alkyl C-H

  Material / context

  and γ-cyclodextrins; γ-cyclodextrin; β-cyclodextrin

  Studies and comparison of the liquid adsorption and surface properties of α-, β- and γ-cyclodextrins by FTIR and capillary rise method DOI: 10.1016/j.colsurfa.2012.07.003
• Alkyl C-H

  Reported band

  2923 cm-1

  Assignment

  Alkyl C-H

  Material / context

  acellular dermal matrix; silk fibroin protein

  Silk fibroin protein modified acellular dermal matrix for tissue repairing and regeneration DOI: 10.1016/j.msec.2018.12.038
• Alkyl C-H

  Reported band

  2923 cm-1

  Assignment

  Alkyl C-H

  Material / context

  phenolic extracts of Lycium barbarum L. fruits

  Comparative Analysis of the Phenolic Profile of Lycium barbarum L. Fruits from Different Regions in China DOI: 10.3390/molecules27185842
• Alkyl C-H

  Reported band

  2923 cm-1

  Assignment

  Alkyl C-H

  Material / context

  amino-functionalised graphene oxide; nanoformulation of Swertiamarin; amino-functionalised graphene oxide (GO)

  Functionalised nanoformulation of Swertiamarin with enhanced stability and hemocompatibility: synthesis, characterisation and anticancer evaluation DOI: 10.1080/10667857.2020.1769260
• Hydroxyl (O-H)

  Reported band

  2923 cm-1

  Assignment

  Hydroxyl (O-H)

  Material / context

  Fe3O4; iron oxide; Fe3O4 nanoparticles

  Kirubha 和 Rajput - 2019 - Enhancement of thermal imaging by iron oxide nanop DOI: 10.1016/j.bcab.2018.12.005
• Hydroxyl (O-H)

  Reported band

  2923 cm-1

  Assignment

  Hydroxyl (O-H)

  Material / context

  WCB; ternary blends of diesel, biodiesel, and other components

  Kumar 和 Sidharth - 2018 - Some Studies on use of ternary blends of diesel, b DOI: 10.1080/15567036.2018.1486902
• Alkyl C-H

  Reported band

  2923 cm-1

  Assignment

  Alkyl C-H

  Material / context

  TiO 2 -Al; TiO 2 -Al 2 O 3; TiO2–Al2O3 composite powder

  Structural, optical, morphological and thermal properties of TiO 2 –Al and TiO 2 –Al 2 O 3 composite powders by ball milling DOI: 10.1016/j.physleta.2017.02.053