What absorbs at 2915 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2915 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 2915 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

• Alkyl C-H 신뢰도 1.0

  “Explicit assignment: νas(CH2)”

  Molecular characterization of silver-stearate (AgStNPs) nanoparticles: A hydrophobic and antimicrobial material against foodborne pathogens DOI: 10.1016/j.foodres.2015.08.005
• Alkyl C-H 신뢰도 1.0

  “In particular, for PE at 710 and 719 cm-1 (-CH2 rocking deformation), 2847 and 2915 cm-1 (- symmetric and asymmetric stretching), 1462 and 1472 cm-1 (-CH=CHstretching) CH2 [36].”

  Campanale 等 - 2023 - Fourier Transform Infrared Spectroscopy to Assess DOI: 10.3390/polym15040911
• Carbohydrate 신뢰도 1.0

  “Moreover, two bands at 2915 and 2850 were linked to pectin and extractives, cm-1 such as waxes [33].”

  Effects of Wet and Dry Treatments on Surface Functional Groups and Mechanical Properties of Flax Fiber Composites DOI: 10.3390/coatings13061036
• Alkyl C-H 신뢰도 1.0

  “In the IR spectra of TG, the cm-1 broad band approximately 3300 is attributed to O-H stretching vibration due to hydrogen bonding involving the hydroxyl groups on the gum molecules, whereas the cm-1 band at 2915 is attributed to CH symmetri”

  Santos 等 - 2019 - Physicochemical, thermal and rheological propertie DOI: 10.1016/j.ijbiomac.2019.05.025
• Alkyl C-H 신뢰도 1.0

  “A peak at 2915 is assigned to C-H (asymmetforth by other isoconversional expressions for some differcm-1 ric) stretching vibration [30].”

  Optical, electrical, mechanical, and thermal properties and non-isothermal decomposition behavior of poly(vinyl alcohol)–ZnO nanocomposites DOI: 10.1007/s13726-020-00806-8
• Amide 신뢰도 1.0

  “Additionally, cm-1 Band / Vibration bands related with proteins (secondary amide) can be 2915 CH symmetric stretch (long aliphatic C chains)”

  de Souza 等 - 2022 - Diffuse Reflectance FTIR of Latent Fingerprints an DOI: 10.21577/0103-5053.20220150
• Alkyl C-H 신뢰도 1.0

  “responsible for the IR peaks at 2915 and 3436 cm-1, The spectra of the treated apatite show new bands at 2922 and 2848 which are associated with the -CH and -CH groups in SNLS, as well as two additional bands at 2 3 cm-1, 1631 and 1609 attr”

  Abdel-Halim 等 - 2023 - Apatite-Calcite Flotation Separation Using Sodium DOI: 10.3390/min13070970
• Acetate 신뢰도 1.0

  “Peaks seemingly due to O-H stretch appeared at 3460 cm-1, cm-1, C-H stretch (aromatic) at 2915 C=O stretch due to vinyl acetate at 1730 C=O at 1727 cm-1, 1610 cm-1, 778 cm-1, 1517 cm-1, and 756 cm-1 corresponds to crystalline form”

  How to Improve Solubility and Dissolution of Irbesartan by Fabricating Ternary Solid Dispersions: Optimization and In-Vitro Characterization DOI: 10.3390/pharmaceutics14112264