What absorbs at 1373 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1373 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 1373 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

  Reported band

  1373 cm-1

  Assignment

  Alkyl C-H

  Material / context

  floatability of Meizhiyou long-flame coal

  Effect of oxidation processing on the surface properties and floatability of Meizhiyou long-flame coal DOI: 10.1016/j.fuel.2017.08.053
• Carboxyl (COOH)

  Reported band

  1373 cm-1

  Assignment

  Carboxyl (COOH)

  Material / context

  flexible nanogenerator from BTO nanopowders on graphene coated PMMA substrates; BTO nanopowders on graphene coated PMMA substrates; BTO nanopowder

  Fabrication of the flexible nanogenerator from BTO nanopowders on graphene coated PMMA substrates by sol-gel method DOI: 10.1016/j.matchemphys.2017.02.002
• Protein

  Reported band

  1373 cm-1

  Assignment

  Protein

  Material / context

  Bacillus megaterium; AgNPs

  Microorganism-mediated green synthesis of silver nanoparticles using Aspergillus niger and Bacillus megaterium DOI: 10.15251/DJNB.2022.171.359
• Hydroxyl (O-H)

  Reported band

  1373 cm-1

  Assignment

  Hydroxyl (O-H)

  Material / context

  HfO2; HfO2 nanoparticles

  Effect of calcination temperature on phase transformation of HfO2 nanoparticles DOI: 10.1063/1.4929229
• Urea

  Reported band

  1373 cm-1

  Assignment

  Urea

  Material / context

  Polyurethane-Urea; Polyurethane; polyurea

  Fluorescence and IR Characterization of Cure in Polyurea, Polyurethane, and Polyurethane−Urea DOI: 10.1021/ma0113172
• Hydrogen bond

  Reported band

  1373 cm-1

  Assignment

  Hydrogen bond

  Material / context

  Cladodes of Opuntia Ficus-Indica; cactus mucilage (CM)

  Preparation and Physicochemical Characterization of Softgels Cross-Linked with Cactus Mucilage Extracted from Cladodes of Opuntia Ficus-Indica DOI: 10.3390/molecules24142531
• Alkyl C-H

  Reported band

  1373 cm-1

  Assignment

  Alkyl C-H

  Material / context

  3-Triazole Functionalized Starch Derivatives; 2a-2e; 1a-1e

  Synthesis and Antioxidant Activity of Cationic 1,2,3-Triazole Functionalized Starch Derivatives DOI: 10.3390/polym12010112