What absorbs at 1578 cm⁻¹ in an FTIR spectrum?
A band near 1578 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 1578 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 |
|---|---|---|---|
| Aromatic ring | 5 | 5 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.5 |
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 |
|---|---|---|---|
| Polypropylene | 1578, 1030, 1600 | Amide | 1 |
| chitosan | 1578, 1650, 1655 | Amide, N h | 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 1578 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
-
Carbonate confidence 1.0
“ı(OH)=1225cm-1][12].Additionally,twoweakbandsat1578and 1310cm-1 corresponding to bidentate carbonate surface groups 3=) (b-CO [12] may also be observed.”
Effect of gallia doping on the acid⠍base and redox properties of ceria DOI: 10.1016/j.apcata.2010.08.050 -
Alkyl C-H confidence 1.0
“WN Intensity WN Intensity WN Intensity WN Intensity stretching 1459.2 68.2 1459.3 70,6 1459.2 72,5 1459.3 80.1 C-O-H 2868.2 69.2 2870.0 70.9 2868.2 73.8 2868.2 83.2 -C-H (CH 2) stretching 1578.5 94.7 1638.2 96.4 1654.9 92.8 1656.8 95.1 C=C”
Glass Powder Additive on Recycled Polypropylene Filaments: A Sustainable Material in 3D Printing DOI: 10.3390/polym14010005 -
C c single bond confidence 1.0
“ring and C-H scissor between benzoic and imidazole ring and C-O-H bending 1458 C-H scissor in the alkyl chain C=C stretching in imidazole ring and C-C stretching in benzoic 1578”
Degradation of Losartan Potassium Highlighted by Correlated Studies of Photoluminescence, Infrared Absorption Spectroscopy and Dielectric Spectroscopy DOI: 10.3390/pharmaceutics14112419 -
Ring structure confidence 1.0
“The infrared spectra of AMP cm-1and cm-1, display one intense peak at 1625 a weak peak at 1578 denoted as A1 and A2 modes.16,41 respectively, which are assigned to pyrimidine ring 2D IR resonances display”
Peng 等 - 2011 - Anharmonic Vibrational Modes of Nucleic Acid Bases DOI: 10.1021/ja205636h -
confidence 1.0
“Notable bands at 1578cm-1, 1562cm-1 may be assigned to O-C-O stretching or N -coordination through alkaloids”
Synthesis of nanostructured CeO2 by chemical and biogenic methods: Optical properties and bioactivity DOI: 10.1016/j.ceramint.2020.02.204 -
Carbonyl (C=O) confidence 1.0
“more distorted binding of nitrate in the Th-DHOA extracted cm-1 The amidic carbonyl peak of DHOA was found at 1578 2018.”
Verma 等 - 2018 - Structural investigations on uranium(VI) and thori DOI: 10.1039/C7NJ04460G. -
Hydroxyl (O-H) confidence 1.0
“The broad band at groups of starch and the amino groups of chitosan was the OH stretching, which overlaps the NH stretch1578cm-1 (Meenakshi et al., 2002).”
Xu 等 - 2005 - Chitosan-starch composite film preparation and ch DOI: 10.1016/j.indcrop.2004.03.002 -
Acetate confidence 1.0
“The intense peak of 1578 is related to the stretching vicm-1 bration of the C=O bond.”
Production of Ni0.5Co0.5Fe2O4/activated carbon@chitosan magnetic nanobiocomposite as a novel adsorbent of methylene blue in aqueous solutions DOI: 10.1038/s41598-023-33470-y
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