What absorbs at 2964 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2964 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 2964 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

  “The CH3 asymmetric and cm-1 symmetric stretching is detected at 2963.6 and 2860 respectively and CH2 asymmetric stretching cm-1.”

  Dahham 等 - 2018 - Studies of ENR-25TiO2 Composites for Electronic M DOI: 10.1088/1742-6596/1019/1/012054
• Alkyl C-H confidence 1.0

  “The appearance of cm-1 C-H stretching band at 2964 and bending peak cm-1 at 1406 in the case of acid-catalyzed product strongly suggest 1,2-Michael addition.”

  Goswami 等 - 2004 - One-pot synthesis of a novel water-soluble fullere DOI: 10.1021/cm0350232
• confidence 1.0

  “Peaks due to C-O stretch, 2900 cm-1 and 2964 cmdue to N-H stretches, 1436 cmand 1727 cm-1 1 1”

  How to Improve Solubility and Dissolution of Irbesartan by Fabricating Ternary Solid Dispersions: Optimization and In-Vitro Characterization DOI: 10.3390/pharmaceutics14112264
• Alkyl C-H confidence 1.0

  “The peak around 2964 corresponds to the -CH asymmetric 3 cm-1, cm-1, cm-1, and symmetric stretching vibrations [14].”

  Detection of Orange Essential Oil, Isopropyl Myristate, and Benzyl Alcohol in Lemon Essential Oil by FTIR Spectroscopy Combined with Chemometrics DOI: 10.3390/foods10010027
• Protein confidence 1.0

  “the soft peak at 2964 The C=O group of amides, which arises due to proteins, is cm-1.”

  Efficiency of Fe3O4 Nanoparticles with Different Pretreatments for Enhancing Biogas Yield of Macroalgae Ulva intestinalis Linnaeus DOI: 10.3390/molecules26165105
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Physicochemical Characterization and Antibacterial Activity of Titanium/Shellac-Coated Hydroxyapatite Composites DOI: 10.3390/coatings12050680
• Alkyl C-H confidence 1.0

  “It is obvious that in the spectrum of the SA-AP cm-1 (Figure 4D), the absorption peak showing at 2964 is related to stretched vibration of C-H with the unsatucm-1 rated olefins' carbon atoms.”

  Li 等 - 2018 - Thermal insulation of silica aerogelPMMA composit DOI: 10.1515/secm-2017-0248
• Alkyl C-H confidence 1.0

  “The spectrum of MSN-[Ch][Cl] shows bands at 2964 and 2922 cm-1, Figure 4.”

  Boosting Antimicrobial Activity of Ciprofloxacin by Functionalization of Mesoporous Silica Nanoparticles DOI: 10.3390/pharmaceutics13020218