What absorbs at 443 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 443 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 authoritative rule. Always confirm against your sample context.

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 443 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

• Metal oxygen confidence 1.0

  “2(b)] shows the presence of sharp diffraction spots indiregion of This band is attributed to the bendcm(cid:1)1) Fe-O cating the formation of well developed, highly crystalline ing vibration of the bond (nearly at 443 in the unit28 nanopart”

  Tailoring the Magnetic and Optical Characteristics of Nanocrystalline BiFeO3 by Ce Doping DOI: 10.1111/j.1551-2916.2012.05132.x
• confidence 1.0

  “The band at 443 was attributed to sympoured between two copper plates in the air.”

  Luminescence in Er3+ co-doped bismuth germinate glass–ceramics for blue and green emitting applications DOI: 10.1007/s43207-022-00281-2
• Carbonyl (C=O) confidence 1.0

  “bands at 1743 from ester carbonyl (C=O) group stretching vibrations 443”

  Kharbach 等 - 2021 - New insights into the Argan oil categories charact DOI: 10.1016/j.talanta.2020.122073
• Silicon (Si) confidence 1.0

  “The band between 443 and 452 are attributed to Si-O-Si in plane cm-1 bending vibration.”

  Lancellotti 等 - 2015 - Geopolymers An option for the valorization of inc DOI: 10.1016/j.ceramint.2014.10.008
• Metal oxygen confidence 1.0

  “two - 4 -1andtwobandsat443and445cm -1 bandsat582and586cm could be pairwise indexed to the stretching vibrations of (311) metal-oxygen bonds in tetrahedron sites and in octahedron”

  Nguyen 等 - 2019 - A Facile Synthesis, Characterization, and Photocat DOI: 10.1155/2019/3428681
• S s confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Rapid Estimation of Sulfur Content in High-Ash Indian Coal Using Mid-Infrared FTIR Data DOI: 10.3390/min13050634
• Metal oxygen confidence 0.95

  “Explicit: 'Ag-O bands at 561 and 443'.”

  Athawale 和 Desai - 2011 - Silver doped lanthanum chromites by microwave comb DOI: 10.1016/j.ceramint.2011.05.008
• Metal oxygen confidence 0.8

  “Characteristic band for Fe-O stretching.”

  Mesoporous magnetite nanoparticles synthesis using the Peltophorum pterocarpum pod extract, their antibacterial efficacy against pathogens and ability to remove a pollutant dye DOI: 10.1016/j.molstruc.2018.10.042