What absorbs at 1133 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1133 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.

Posibles asignaciones de grupos funcionales

La clasificación refleja la evidencia acumulada de la literatura, no una única regla autorizada. Siempre confirme según el contexto de su muestra.

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 1133 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.

Literatura detrás de estas asignaciones

• Carboxyl (COOH) confianza 1,0

  “moiety incorporated through transesterification onto coir, but after curing this band disappears C cm-1 and weak band at 1133 appears due to benzoate (C 6H 5-COO-) vibration ensuring the C introduction of benzoate moiety after curing [Fig.1”

  Rout 等 - 2017 - A green approach to produce silver nano particles DOI: 10.1016/j.surfin.2017.03.004
• S eq o confianza 1,0

  “cm-1, amine at 3343.3 S=O stretching asymmetric band thermal behavior of rather the drug or polymer may cm-1 at 1133.4 and S=O stretching symmetric band indicate a possible drug-polymer interaction (9).”

  Jelvehgari 等 - 2015 - Experimental Design to Predict Process Variables i DOI: 10.15171/apb.2015.033
• Acetate confianza 1,0

  “New bands in CL-WE-AgNPs at 1133 and 1467 (Figure 5b) may be attributed as vibrations of the glycosidic C-O bond (C-O-C) stretches Polymers 2023, 15, x FOR PEER REVIEW 9 of 20”

  Part B: Improvement of the Optical Properties of Cellulose Nanocrystals Reinforced Thermoplastic Starch Bio-Composite Films by Ex Situ Incorporation of Green Silver Nanoparticles from Chaetomorpha linum DOI: 10.3390/polym15092148
• Acetate confianza 1,0

  “According to the band assignments in FTIR spectra, the 1182 cm-1 band is assigned to ν as(C-O-C) + r as(CH 3), and the bands at cm-1 1133 are the pure band relative to the CH group, r s(CH 3).”

  Pandit 等 - 2014 - Influence of Temperature on the Conformational Gui DOI: 10.14429/dsj.64.7329
• Amide confianza 1,0

  “The particular peak of 1133 results from the vibrations of the asymmetric stretching of the chemical bonds in C-N-C groups of the oxazine ring.”

  A Phosphorous-Containing Bio-Based Furfurylamine Type Benzoxazine and Its Application in Bisphenol-A Type Benzoxazine Resins: Preparation, Thermal Properties and Flammability DOI: 10.3390/polym14081597