What absorbs at 1372 cm⁻¹ in an FTIR spectrum?
A band near 1372 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Quick answer
A band near 1372 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
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Alkyl C-H | 11 | 11 | 1.0 |
| C c single bond | 6 | 6 | 1.0 |
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Hydroxyl (O-H) | 5 | 5 | 1.0 |
| Carbohydrate | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Aldehyde (CHO) | 1 | 1 | 0.8 |
| Methyl | 1 | 1 | 0.8 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| MWCNTs | 1372, 3396, 1735 | Alkyl C-H, Methacrylate, Acetate | 1 |
| ZnO | 1372, 1400, 3430 | Alkyl C-H, Acetate, Methacrylate | 1 |
| polyaniline | 1372, 1565, 1570 | Alkyl C-H, Methacrylate, Acetate | 1 |
| ZnO nanoparticles | 1372, 1219, 1726 | Alkyl C-H, Methacrylate, Acetate | 1 |
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 1372 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
-
confidence 1.0
“Cu-H C-H 2062 stretching 1421 bending 73.6423 0.4723 10.41 5.13 C-H 1632 N-H stretching 1372 bending”
El Bialy 等 - 2020 - Comparative Toxicological Effects of Biologically DOI: 10.2147/IJN.S241922 -
Alkyl C-H confidence 1.0
“(32.6)A (0.9)A 2.5 159.6 4.9 cm-1 gen (C-O) stretching), at 1228 (carbon-hydrogen (27.0)A (1.0)A 4.0 140.3 4.5 cm-1 (C-H) stretching), at 1372 (methyl group (of the (13.1)A (0.4)A 2.6 1.0 156.7 Tectona grandis acetyl unit) stretching in cel”
Acetylation of tropical hardwood species from forest plantations in Costa Rica: an FTIR spectroscopic analysis DOI: 10.1186/s10086-020-01898-9 -
C c single bond confidence 1.0
“Isoindole stretching 1372 Isoindole stretching C-C 1332 Pyrrole stretching coupled with aza rocking C-H 1256 deformation C-H 1164 deformation”
Gharagozlou 和 Naghibi - 2018 - Sensitization of ZnO nanoparticles by metal-free p DOI: 10.1016/j.jlumin.2017.12.020 -
Siloxane (Si-O-Si) confidence 1.0
“started to react with SiF species both on and inside the x cm-1 During the exposure to O neutrals, the Si-O-Si LO-TO film, the peak at 1372 gradually fluorinated SiO 2 cm-1 phonon peak that appears at 1084 after deposition was emerged from”
Han 和 Aydil - 1997 - Structure and chemical composition of fluorinated DOI: 10.1116/1.580845 -
Amide confidence 1.0
“Moreover, the new absorption peaks at 1372, 1508, 1561 cm-1 nium hydroxide (100 ml) was placed into a 250 ml round bottom and 1692 representing the C N stretching, C C stretching of flask, and then 4.0 g of tetraethoxyorthosilane (TEOS) was”
Stopband attenuation of silica spheres by attaching aniline and polyaniline DOI: 10.1016/j.synthmet.2013.03.007 -
Alkyl C-H confidence 1.0
“Strong peak at 1372 cm-1 assigned to C-H stretching vibrations of chemisorbed hydrogen.”
Misra 等 - 2006 - FTIR studies of nitrogen doped carbon nanotubes DOI: 10.1016/j.diamond.2005.08.013 -
Alkyl C-H confidence 1.0
“Strong peak at 1372 cm-1 consistent with C-H.”
FTIR Spectroscopy of Multiwalled Carbon Nanotubes: A Simple Approachto Study the Nitrogen Doping DOI: 10.1166/jnn.2007.723 -
C c single bond confidence 1.0
“The ratio between -1 peak appears at 695 cm due to aromatic C-C angular -1 the heights of the bands at 1372 and 2900 cm was used deformation in both materials (Fig.”
Uner 等 - 2016 - Centaurea solstitialis and Silybum marianum weeds DOI: 10.1007/s13726-015-0396-2
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