What absorbs at 3641 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3641 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.

가능한 작용기 할당

순위는 단일 권위 규칙이 아닌 축적된 문헌 증거를 반영합니다. 항상 샘플 상황에 대해 확인하세요.

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 3641 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.

이 할당의 배경이 되는 문헌

• 신뢰도 1.0

  “presence of Ca(OH) is indicated by the emer2 gence of stretching absorption bands from O-H at 3641 cm-1 and also the Ca-O stretching in 700-900 cm-1 absorption band [18,33] that is supported by XRD data in Figure 6.”

  Natural Clay of Pasaman Barat Enriched by CaO of Chicken Eggshells as Catalyst for Biodiesel Production DOI: 10.9767/bcrec.15.3.8097.662-673)
• 신뢰도 1.0

  “= g/mol) (Mn vibration peak of the hydroxyl group in GAP 1000 is at 3641 It can be seen from the vibration peak of the hydroxyl group in GAP (Mn = 1000 g/mol) is at 3641 cm-1.”

  The Effect of Glycidyl Azide Polymer Grafted Tetrafunctional Isocyanate on Polytriazole Polyethylene Oxide-Tetrahydrofuran Elastomer and its Propellant Properties DOI: 10.3390/polym12020278
• Hydroxyl (O-H) 신뢰도 1.0

  “LLM confirmed rule peak-group candidate”

  Molla 等 - 2022 - Facile extraction and characterization of calcium DOI: 10.1098/rsos.220681
• Hydroxyl (O-H) 신뢰도 1.0

  “The band at 3641 present in the calcium 411 hydroxide sample is related to its OH bonds.”

  Moraes 等 - 2019 - Production of bamboo leaf ash by auto-combustion f DOI: 10.1016/j.conbuildmat.2019.03.007
• Silicon (Si) 신뢰도 1.0

  “Band at 3641 was assigned to Si-OH As this peak was not seen in C20A additive alone, it was hydroxyl stretching in clays modified using silanes [30].”

  Ross 等 - 2017 - Micro and nanocomposites of polybutadienebased pol DOI: 10.1515/chem-2017-0006
• Hydroxyl (O-H) 신뢰도 1.0

  “Hydroxyl and carboxyl funcabsorption band at ~ 3641 (free O-H stretchtional groups present in sticky rice and its alkaline ing from portlandite) is higher in the specimens with”

  Zhang 等 - 2021 - Effects of sticky rice addition on the properties DOI: 10.1186/s40494-020-00475-z
• Hydroxyl (O-H) 신뢰도 0.9

  “Explicit: 'band at 3641 cm-1 ... O-H' and 'identi?ed the hydroxyl of the portlandite phase'.”

  Hydroxyapatite synthesis from a starfish and β-tricalcium phosphate using a hydrothermal method DOI: 10.1039/c6ra26907a