What absorbs at 2913 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2913 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 authoritative 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 2913 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 confidence 1.0

  “cm-1, of the C-H band is seen at 2913 At 1422 the stretching vibration of the C-H band can be noticed.”

  Ramadan 和 Ismail - 2022 - Tunning the Physical Properties of PVDFPVCZinc F DOI: 10.21203/rs.3.rs-935328/v1
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Nguyen 等 - 2022 - Effects of Ultraviolet Radiation on Recycled and V DOI: 10.21203/rs.3.rs-978155/v1
• Alkyl C-H confidence 1.0

  “The band at 2913 can be attributed to C-H symmetric stretching.”

  Influence of the Impregnation Technique on the Release of Esomeprazole from Various Bioaerogels DOI: 10.3390/polym13111882
• Alkyl C-H confidence 1.0

  “2912.95cm-1 2848.35cm-1 the PEG and the peak at and of 2.06 - 2.60Å distance and one hydrophobic π interacrepresents the methyl and propyl group of HPMC tion with the polymer.”

  Senthilvel 等 - 2019 - Development of Capsules Filled with Phenytoin and DOI: 10.5530/ijper.53.3.79
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Construction of Novel Polymerizable Ionic Liquid Microemulsions and the In Situ Synthesis of Poly(Ionic Liquid) Adsorbents DOI: 10.3390/nano9030454
• Alkyl C-H confidence 0.95

  “Explicit: 'C-H stretching vibration at ... 2913'.”

  Preparation, Characterization of Propargyl Terminal Polybutadiene and Its Crosslinked Elastomers Properties DOI: 10.3390/polym12040748
• confidence 0.9

  “Text: 'stretching vibrations appear at 2975 and 2913 cm-1'”

  Aliyev 等 - 2020 - SI-ATRP Polymer-Functionalized Graphene Oxide for DOI: 10.1002/admi.202000443.
• confidence 0.8

  “Sorption peaks assigned to AKD.”

  Hundhausen 等 - 2009 - Use of alkyl ketene dimer (AKD) for surface modifi DOI: 10.1007/s00107-008-0275-z