What absorbs at 401 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 401 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.

可能性のある官能基アサイン

ランキングは蓄積された文献証拠を反映しており、単一の権威あるルールではありません。常にサンプルのコンテキストと照合して確認してください。

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 401 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.

これらのアサインの根拠となる文献

• N h 信頼度 1.0

  “the peak at 401.2 4+ eV corresponds to NH in the APP.”

  Liang 等 - 2020 - Thermal Kinetics of a Lignin-Based Flame Retardant DOI: 10.3390/polym12092123
• 信頼度 1.0

  “The weak peak at 401.1 eV is indicative of the presence of terminal amino functional group, originating from the incomplete”

  Dual Roles of [NCN]2- on Anatase TiO2: A Fully Occupied Molecular Gap State for Direct Charge Injection into the Conduction Band and an Interfacial Mediator for the Covalent Formation of Heterostructured g-C3N4/a-TiO2 Nanocomposite DOI: 10.1016/j.apcatb.2020.119036
• Ammonium 信頼度 1.0

  “In this investigation, a novel compound characteristic peak at 401.36 eV corresponding to the -NH3?.”

  Synthesis of a novel compound based on chitosan and ammonium polyphosphate for flame retardancy applications DOI: 10.1007/s10570-019-02671-y
• Metal oxygen 信頼度 1.0

  “Figure 6b shows that the water contact 2 N-C 15.2° peaks at 400.7 eV were assigned to the bond, suggesting angle of APTMS-TiO 2@SiO was decreased to and that 2 126.2°”

  Wang 等 - 2023 - Surface-Modified TiO2@SiO2 Nanocomposites for Enha DOI: 10.1021/acsomega.3c02679
• 信頼度 1.0

  “The peaks at 401.0 and 404.6 eV are attributed to the amino group (C-N-H) the graphitic N.”

  Underlying Mechanisms of Reductive Amination on Pd-Catalysts: The Unique Role of Hydroxyl Group in Generating Sterically Hindered Amine DOI: 10.3390/ijms23147621
• N h 信頼度 1.0

  “In bonds), 400.43 (NH contrast, CoPc-immobilized GO showed the shifting of bands and a considerable intensity enhancement of the peak at 400.69 eV due to the electron-withdrawing effect of GO (Fig-”

  Cobalt Phthalocyanine Immobilized on Graphene Oxide: An Efficient Visible-Active Catalyst for the Photoreduction of Carbon Dioxide DOI: 10.1002/chem.201304189
• Secondary amine 信頼度 1.0

  “BH (Figure For nylon 6-NH, vibrations of amide I and 401.0 eV attributed to the secondary amine and the new 3”

  Yan 等 - 2022 - Functionalized Nylon 6 Fabric as an Efficient and DOI: 10.1021/acsomega.2c03401