What absorbs at 1426 cm⁻¹ in an FTIR spectrum?
A band near 1426 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 1426 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 | 18 | 18 | 1.0 |
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Carbonate | 3 | 3 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Aldehyde (CHO) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| N h | 1 | 1 | 0.6 |
| Aromatic ring | 1 | 0 | 1.0 |
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 |
|---|---|---|---|
| PVP | 1426, 2983, 1648 | Alkyl C-H, Methacrylate, Acetate | 1 |
| cellulose | 1426, 1735, 1650 | Alkyl C-H, Acetate, Methacrylate | 1 |
| polyvinyl alcohol | 1426, 1141, 1640 | Alkyl C-H, Methacrylate, Acetate | 1 |
| PVC | 1426, 834, 1195 | Alkyl C-H, Methoxy (OCH3), Methacrylate | 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 1426 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
-
Acetate confidence 1.0
“cm(cid:1)1 The band at 897 in absorbance and dichroic ratio are observed for the assigned as C-O-C stretching cm(cid:1)1.28 linkage23,25,26,28 b-(1!4)-glycosidic bands at 1426 and 1334 at the The band at moves toward cm(cid:1)1, stretching,”
Oh 等 - 2005 - Crystalline structure analysis of cellulose treate DOI: 10.1016/j.carres.2005.08.007 -
Alkyl C-H confidence 1.0
“The two peaks at 1426 and 1328 peaks gives integral ratio expected for the PVA backbone cm-1 C-H reprebending of [35].”
Xue 等 - 2015 - Moving-window two-dimensional correlation infrared DOI: 10.1007/s00216-015-9035-1 -
Amide confidence 1.0
“N-H overlap bending -1)Assignment 665Stretching stretching1426,1382Coupling (C-N)1160(C-O-C (O-H)3424(O-H) O stretching2880(CH)”
Experimental and DFT studies on the structural and optical properties of chitosan/polyvinyl pyrrolidone/ZnS nanocomposites DOI: 10.1007/s00289-023-04700-0 -
Aldehyde (CHO) confidence 1.0
“cm-1 top" Surprisingly, unlike the case of pure water, the band at 1426 assigned to δ cm-1), cm-1 (CHO) was shifted to a lower frequency (1415 whereas the bands at 1580 and 1342”
Belhadj 等 - 2017 - Mechanisms of Simultaneous Hydrogen Production and DOI: 10.1021/acscatal.7b01312 -
Water (H2O) confidence 1.0
“Among the peaks relating to SBAG, the peak of symcm-1) metric stretching of the carboxyl group (1426 shifled to involving more water molecules in the conjugate ted to lower wavenumbers, while the peak of C-O structure (Hazaveh et al., 2015)”
Improving the functional properties of fish gelatin by conjugation with the water-soluble fraction of bitter almond gum DOI: 10.1007/s10068-020-00847-y -
Alkyl C-H confidence 1.0
“cm-1 The band at 1426 was due to the vibration of CH of PVC [23] and was taken as a reference band.”
Study of the effectiveness of a presoaking process for reducing the additives migration from babies toys DOI: 10.3906/kim-2105-40 -
Alkyl C-H confidence 1.0
“characteristic of axial deformation of C-H and O-C-H bonds”
Braga 等 - 2015 - The energetic characterization of pineapple crown DOI: 10.1007/s11356-015-5082-6 -
Carbonate confidence 1.0
“The absorption bands of the CO antisymmetric stretching vibration of carbonate were observed at 1483 cm-1 and 1426 cm-1 [58,59].”
Thermal Degradation Characteristics of Styrene-Butadiene-Styrene Copolymer Asphalt Binder Filled with an Inorganic Flame-Retarding Agent DOI: 10.3390/polym14183761
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