What absorbs at 1187 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1187 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 1187 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

• N h 신뢰도 1.0

  “that can be assigned to the NH Their observation of the absence of proton of E showed a band at 1187 bending vibration of a strongly hydrogen-bonded His and a release in the presence of o-phenanthroline, concomitant with cm-1 cm-1 band at 1”

  Kimura 等 - 2020 - Protonation State of a Key Histidine Ligand in the DOI: 10.1021/acs.biochem.0c00810
• Acetate 신뢰도 1.0

  “cm-1, cm-1), 2662 which characterize cyclic dimer, in-plane COH (1400 the CO bending vibrations cm-1) cm-1, (1714 and feature at 1700 which also characterizes the cyclic dimer, the COH bending cm-1 cm-1), (1400) and C-O stretching vibration”

  Kondratenko 等 - 2020 - Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dot DOI: 10.3390/ma13040909
• Ester 신뢰도 1.0

  “cm-1 (1) EPMC due to the absorption at 1707 of the In this step, two amine compounds were used, namely cm-1 carbonyl ester strengthened by the band at 1186.86 phenethylamine and morpholine, to produce N-”

  Rasyid 等 - 2022 - Synthesis of N-phenethyl-p-methoxycinnamamide and DOI: 10.22146/ijc.76802
• Ester 신뢰도 1.0

  “and bands located between 1187 and 1277/cm that represented ester C=O vibrations.”

  Biodegradation of P(3HB-co-4HB) powder by Pseudomonas mendocina for preparation low-molecular-mass P(3HB-co-4HB) DOI: 10.1007/s13205-017-0824-4
• Acetate 신뢰도 1.0

  “The peaks at 1187 and 980 are 2 3 respectively attributed to the asymmetric stretching of C-O-C and the deformation of C=CH [43,44],”

  Hosseini 等 - 2017 - Polymethacrylate Coated Electrospun PHB Fibers as DOI: 10.3390/s17102292
• Amide 신뢰도 1.0

  “The -C-N band at wavenumbers 1187 and”

  Preparation and Characterization of Indomethacin Supramolecular Systems with -Cyclodextrin in Order to Estimate Photostability Improvement DOI: 10.3390/molecules26247436
• Siloxane (Si-O-Si) 신뢰도 1.0

  “Moreover, in the case of silane- -1 cm-1 samples, a peak at 1187 occurred and was attributed to the presence of siloxane”

  APTES-Modified Nanocellulose as the Formaldehyde Scavenger for UF Adhesive-Bonded Particleboard and Strawboard DOI: 10.3390/polym14225037
• Acetate 신뢰도 1.0

  “C-N, C-C and C-O stretching 1187 a 1015 A menu plot molecular graph, the electrostatic”

  Rangel-Vazquez 等 - 2014 - Spectroscopy Analyses of PolyurethanePolyaniline DOI: 10.1590/0104-1428.1496