What absorbs at 2140 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2140 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 2140 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

• Hydroxyl (O-H) 신뢰도 1.0

  “N-D identified that the stretching vibrations of the Schiff X-D most spectral changes in the stretching vibrations cm-1 (32) base in BR and ppR are located at 2171 and 2123 O-D N-D originate from either a water stretch or a stretch cm-1 and”

  Ota 等 - 2006 - Structural changes in the Schiff base region of sq DOI: 10.1021/bi051937l
• Hydroxyl (O-H) 신뢰도 1.0

  “Physisorbed CO results in a band at 2140 cm-1, whereas CO interacting with surface OH groups gives rise to a band at 2155 while cm-1 cm-1 another massif from 2180 to 2245 accounts for CO interacting with Lewis cm-1”

  Upgrading the PtCu intermetallic compounds: The role of Pt and Cu in the alloy DOI: 10.1016/j.cattod.2019.11.026
• Silicon hydride 신뢰도 1.0

  “Whereas the decrease in the CH bands intensities and the simultaneous 3 cm-1 increase of the Si-H absorption band intensity at 2140 at higher W/F values (hard plasma conditions), is due to the higher monomer fragmentation.”

  Comparative study of bulk and surface compositions of plasma polymerized organosilicon thin films DOI: 10.1002/ppap.201900024.
• Hydroxyl (O-H) 신뢰도 1.0

  “cm-1 and interaction with Here, the strong broadband centered at around 3291 and weak band at cm-1 around 2140 are ascribed to the inter molecular hydrogen bonded network formed by the hydroxyl groups”

  Bioinspired 5-caffeoylquinic acid capped silver nanoparticles using Coffee arabica leaf extract for high-sensitive cysteine detection DOI: 10.1038/s41598-023-34944-9
• 신뢰도 1.0

  “Based on our previous studies supported by DFT calculations [8,11], we assign the cm-1 2127 band to Pd(II)(OH)(CO) complex (or alternatively Pd(II)(CO) complex: we cannot cm-1 exclude either assignment at present) and the 2140 band to a dif”

  The superior hydrothermal stability of Pd/SSZ-39 in low temperature passive NOx adsorption (PNA) and methane combustion DOI: 10.1016/j.jcat.2010.07.031.
• C c single bond 신뢰도 1.0

  “LLM confirmed rule peak-group candidate”

  Microsoft Word - Rapid_synthesis_of_nanocrystalline_YAG_via_microwave_assisted_solvothermal_process_final_resubmit_jbBV (1) DOI: 10.1111/jace.15815
• Adsorbed carbon monoxide 신뢰도 1.0

  “cm-1, bands of carbon dioxide at 2317 and 3728 cm-1, the rotovibrational band due to CO deformation at bands of carbon dioxide at 2317 and 3728 the rotovibrational band due to CO deformation at 2 2 cm-1, cm-1), 771 the rotovibrational band”

  Thermocatalytic Pyrolysis of Exhausted Arthrospira platensis Biomass after Protein or Lipid Recovery DOI: 10.3390/en13205246
• C#c 신뢰도 1.0

  “Also, a small stretch at 2140 was found, which can be assigned to alkyne Apart cm-1 from this, a very sharp and intense peak was obtained at 1650 for C=O stretch representing α, β unsaturated cm-1 aldehydes and ketones.”

  Comparative assessment of green and chemically synthesized glutathione capped silver nanoparticles for antioxidant, mosquito larvicidal and eco-toxicological activities DOI: 10.1038/s41598-023-35249-7