What absorbs at 2909 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2909 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.

가능한 작용기 할당

순위는 단일 권위 규칙이 아닌 축적된 문헌 증거를 반영합니다. 항상 샘플 상황에 대해 확인하세요.

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 2909 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.

이 할당의 배경이 되는 문헌

• Hydrogen bond 신뢰도 1.0

  “The band 2909cm-1 at is due to carbon-hydrogen bond (C-H) stretching vibration.”

  Eliza 等 - 2015 - Carboxymethyl Cellulose (CMC) from Oil Palm Empty DOI: 10.1088/1742-6596/622/1/012026
• Carbonate 신뢰도 1.0

  “The low intensity bands at 2909 probably corresponding to carbonate C=O group from cm-1 carbonate ion.”

  Characterization of quicklime as raw material to hydrated lime: Effect of temperature on its characteristics DOI: 10.1063/1.5066668
• Alkyl C-H 신뢰도 1.0

  “LLM confirmed rule peak-group candidate”

  Gonultas 和 Candan - 2018 - CHEMICAL CHARACTERIZATION AND FTIR SPECTROSCOPY OF DOI: 10.4067/S0718-221X2018005031301
• Hydroxyl (O-H) 신뢰도 1.0

  “3458 3557 OH stretching 2909 2944 CH stretching of CH and CH groups 2 3 COOH-O-H bending of absorbed water and/or C=O stretching of amid/or asymmetrical”

  Heidarieh 等 - 2014 - Preparation and anatomical distribution study of G DOI: 10.2478/nuka-2014-0019
• Amide 신뢰도 1.0

  “3 968 C-N stretching - 2909 -CH Vibrations 3 1000”

  Origin of Defects and Positron Annihilation in Hybrid and All-Inorganic Perovskites DOI: 10.1021/acs.chemmater.1c03540
• Alkyl C-H 신뢰도 1.0

  “The peak at 2909 for the pure GG is assigned to the antisymmetric and symmetric C-H stretching vibrations of the methylene hydroxyl groups (-CH 2OH) [12,14,17,18].”

  Guar Gum as an Eco-Friendly Corrosion Inhibitor for Pure Aluminium in 1-M HCl Solution DOI: 10.3390/ma12162620
• Alkyl C-H 신뢰도 1.0

  “LLM confirmed rule peak-group candidate”

  Radioactive Cobalt(II) Removal from Aqueous Solutions Using a Reusable Nanocomposite: Kinetic, Isotherms, and Mechanistic Study DOI: 10.3390/ijerph14121453
• Acetate 신뢰도 1.0

  “of methyl and methylene (2909 the O-C=O stretching vibration of -COOH (1638 the C-O-C cm-1);”

  Enhanced heavy metal removal from an aqueous environment using an eco-friendly and sustainable adsorbent DOI: 10.1038/s41598-020-73570-7