What absorbs at 2009 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2009 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 2009 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

• Hydroxyl (O-H) confidence 1.0

  “2009 for OH bands above 3000 behavior for the humite-group minerals at high temperatures Phase E (e.g., Kleppe et al.”

  In-situ high-temperature vibrational spectra for synthetic and natural clinohumite: Implications for dense hydrous magnesium silicates in subduction zones DOI: 10.2138/am-2019-6604
• Alkyl C-H confidence 1.0

  “The peak at 3,014 is due cm-1 3,213 are due to the -C=Cand =CH modes of adsorbed to CH stretching of alkenes (Mistry, 2009), the doublet at 2,9642,921cm-1 groups,whilethe2,877cm-1 acetylene, whose formation is accompanied by the complete is”

  Carbon Domains on MoS2/TiO2 System via Catalytic Acetylene Oligomerization: Synthesis, Structure, and Surface Properties DOI: 10.3389/fchem.2017.00091
• Amide confidence 1.0

  “(2009), Ogawa et absorption in Amide I bond is usually in al.”

  Gharagheshlagh 等 - 2020 - Isolation and characterization of acid-soluble col DOI: 10.22092/ijfs.2019.118957
• confidence 1.0

  “When the charge is completed, the bands at 710 can be clearly observed and attributed to the stretching vibration of C-Cl (Marcus, 2009).”

  High-voltage and long-lasting aqueous chlorine-ion battery by virtue of “water-in-salt” electrolyte DOI: 10.1016/j.isci.
• Acetate confidence 1.0

  “C-O stretchGarip 2009;”

  Merma 等 - 2017 - DOI: 10.1590/0370-446720167000063
• Amide confidence 1.0

  “The band cm-1 making them stable against aggregation (Kumar and Yadav at 1041 was related to C-N stretch of aliphatic 2009).”

  Instant green synthesis of silver-based herbo-metallic colloidal nanosuspension in Terminalia bellirica fruit aqueous extract for catalytic and antibacterial applications DOI: 10.1007/s13205-016-0589-1)
• N-O bond confidence 1.0

  “intensities for the RM but no band broadening, evolve2009).”

  Pedersen 等 - 2015 - Bacterial and abiotic decay in waterlogged archaeo DOI: 10.3929/ethz-b-000095042
• Water (H2O) confidence 1.0

  “Materials 2009, 2 730 Water absorption of (a) PEU-1 series, (b) PEU-2 series after 72 hours soaking in Figure 8.”

  Isopropyl Myristate-Modified Polyether-Urethane Coatings as Protective Barriers for Implantable Medical Devices DOI: 10.3390/ma2030719