What absorbs at 2901 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2901 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 2901 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

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  biochar from wood pellets

  Study of biochar from pyrolysis and gasification of wood pellets in a nitrogen plasma reactor for design of biomass processes DOI: 10.1016/j.jece.2019.103391
• Alkyl C-H

  Reported band

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  sample moisture content on XRD-estimated cellulose crystallinity index; cellulose-II; cellulose-I

  Effect of sample moisture content on XRD-estimated cellulose crystallinity index and crystallite size DOI: 10.1007/s10570-017-1259-0
• Metal oxygen

  Reported band

  2901 cm-1

  Assignment

  Metal oxygen

  Material / context

  magnetic aminated chitosan composite as efficient; ATP; NH2Cs

  Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr (VI) ions DOI: 10.1038/s41598-021-96145-6
• Alkyl C-H

  Reported band

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  —

  Impedance, Electrical Equivalent Circuit (EEC) Modeling, Structural (FTIR and XRD), Dielectric, and Electric Modulus Study of MC-Based Ion-Conducting Solid Polymer Electrolytes DOI: 10.3390/ma15010170
• Hydroxyl (O-H)

  Reported band

  2901 cm-1

  Assignment

  Hydroxyl (O-H)

  Material / context

  Chitosan; chitosan thin film

  Nanostructured Chitosan/Maghemite Composites Thin Film for Potential Optical Detection of Mercury Ion by Surface Plasmon Resonance Investigation DOI: 10.3390/polym12071497
• Alkyl C-H

  Reported band

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  Furfurylation on Bamboo-Scrimber Composi; furfurylated bamboo scrimber; bamboo scrimber

  Li 等 - 2023 - Effect of Furfurylation on Bamboo-Scrimber Composi DOI: 10.3390/ma16072931
• Alkyl C-H

  Reported band

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  Cellulose; microfibrillated cellulose (MFC); microcrystalline cellulose (MCC)

  Microfibrillated Cellulose with a Lower Degree of Polymerization; Synthesis via Sulfuric Acid Hydrolysis under Ultrasonic Treatment DOI: 10.3390/polym15040904
• Alkyl C-H

  Reported band

  2901 cm-1

  Assignment

  Alkyl C-H

  Material / context

  Fe3O4; wood composites; Fe3O4 nanoparticles

  In Situ Synthesis of Fe3O4 Nanoparticles and Wood Composite Properties of Three Tropical Species DOI: 10.3390/ma15093394