What absorbs at 1209 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1209 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.

Möjliga identifieringar av funktionella grupper

Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.

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 1209 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.

Litteratur bakom dessa identifieringar

• Acetate förtroende 1,0

  “The peaks at 1209, 1088, and 833 demonoftheprocess.AccordingtoRoyetal.(2008),alkanes,fattyacids,and strated C-O stretching of the alkyl aryl group, C-N stretching of substances with ester groups were found due to biodegradation by the amine”

  Characterization of plastic degrading bacteria isolated from sewage wastewater DOI: 10.1016/j.sjbs.2023.103628
• Imide förtroende 1,0

  “FTIR(KBr, 1772, 1720(imideIgroup)1507(stretchingoftrisubstitutedbenzenering), 1386 (imide II, CN stretching), 1209 (COC antisymmetric stretching), 929 (out-of-plane CH bending).”

  Corrosion Resistance of Mild Steel Coated with Phthalimide-Functionalized Polybenzoxazines DOI: 10.3390/coatings10111114
• Hydroxyl (O-H) förtroende 1,0

  “The vibration peak at around 1460 is assigned to scissoring modes cm-1 cm-1 of CH 2, and the peaks at 1343 and 1278 to rocking vibration modes of CH [48], 2 cm-1 while the vibration peak at 1209 is indicative of the OH deformation asymmetri”

  Stabilization of Dry Sucrose Glasses by Four LEA_4 Proteins from Arabidopsis thaliana DOI: 10.3390/biom11050615
• Silicon (Si) förtroende 1,0

  “The spectra show the peak associated with the TO vibration mode of the asymmetric stretch of Si-O-Si bonds located at 1088 cm-1, and the shoulder at approximately 1209 cm-1 is assigned to the LO vibration mode of SiO-Si.”

  Mocioiu 等 - 2021 - Effect of ZnO on Properties of Gels for Heritage O DOI: 10.3390/gels7040251
• Amide förtroende 1,0

  “Concurrently, the band of 1209 cm-1 in AgNPs (which was cm-1 2shifted from 1224 in cell biomass) corresponds to C-N stretching and PO asymmetric stretching.”

  Microbial Mediated Synthesis of Silver Nanoparticles by Lactobacillus plantarum TA4 and Its Antibacterial and Antioxidant Activity DOI: 10.3390/app10196973
• Acetate förtroende 1,0

  “at 1209 would be due to the stretching vibration of (O-CH3);”

  Oliveira 等 - 2016 - FTIR analysis and quantification of phenols and fl DOI: 10.1590/S1517-707620160003.0072
• förtroende 0,7

  “Assigned to macrocycle 3.”

  Self-Healing Thiolated Pillar[5]arene Films Containing Moxifloxacin Suppress the Development of Bacterial Biofilms DOI: 10.3390/nano