What absorbs at 1574 cm⁻¹ in an FTIR spectrum?
A band near 1574 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 1574 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 |
|---|---|---|---|
| Secondary amine | 6 | 6 | 1.0 |
| Amide | 6 | 6 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Carboxyl (COOH) | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Aromatic ring | 4 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 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 | 1574, 2983, 1648 | Amide, Secondary amine, Carboxyl (COOH) | 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 1574 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
-
Alkene (C=C) confidence 1.0
“The sharp peak cm-1 observed at 1605 could be attributed to -C=N group and the peaks at 1574, 1511 and cm-1 1411 are attributed to -C=C─ and C-H in plane bending vibrations of the aromatic ring cm-1 which forms an important part of the mole”
Synthesis, crystal structures, quantum chemical studies and corrosion inhibition potentials of 4-(((4-ethylphenyl)imino)methyl)phenol and (E)-4-((naphthalen-2-ylimino) methyl) phenol Schiff bases DOI: 10.1016/j.molstruc.2017.06.104 -
C=n confidence 1.0
“synthesized HCl doped PANI (ES form) as previously reported [22, 23], C-C stretching on cm-1) cm-1), and the benzene ring band (1481-1485 the C=N band of quinoid band (1574 8 ACCEPTED MANUSCRIPT cm-1),”
Jevremovic 等 - 2014 - Investigation of the effect of acid dopant on the DOI: 10.1016/j.cap.2014.06.018 -
Alkyl C-H confidence 1.0
“absorption peaks of sugars, and absorptions at 1574 and 1412 were the characteristics of C-H cm-1 cm-1 cmat 1640 was due to C=O (-COOH) stretching vibration, which was the proof of the presence of 1 vibration, respectively [32].”
Song 等 - 2020 - Acetylated Polysaccharides From Pleurotus geestera DOI: 10.3390/ijms21082810 -
N h confidence 1.0
“At the same instant, the new IR peak cm-1 at 1574 is obtained due to the anionic form of 2)COORCH(NH in amino acid.”
Structural and electrical behaviours of amino acid-based solid polymer electrolytes DOI: 10.1007/s12034-021-02464-9 -
Alkene (C=C) confidence 1.0
“cm-1, At 1574.38 peaks were found that corresponded to the involvement of alkenes (-C=Cstretch).”
The Nutritional Quality and Structural Analysis of Black Soldier Fly Larvae Flour before and after Defatting DOI: 10.3390/insects13020168 -
confidence 1.0
“The The peak at 1574 results of the coupling of (N-H) angular deformation and (C-N) axial stretchcm-1 cm-1”
Experimental and DFT studies on the structural and optical properties of chitosan/polyvinyl pyrrolidone/ZnS nanocomposites DOI: 10.1007/s00289-023-04700-0 -
Alkene (C=C) confidence 1.0
“Two other bands, 1574 and 1513 were observed for the mixed mode of the C=O and C=C stretching vibrations, these vibrations were calculated at 1628 cm-1 and 1620 respectively.”
Density Functional Theory and Molecular Docking Investigations of the Chemical and Antibacterial Activities for 1-(4-Hydroxyphenyl)-3-phenylprop-2-en-1-one DOI: 10.3390/molecules26123631 -
Amine primary confidence 1.0
“2 (spectrum h) shows characteristic bands at 3460.4 and 3363.5 cm-1 (NH2 stretching), 1662.8 cm-1 (C=O cm-1 p-Aminobenzoic acid (spectrum h) shows characteristic bands at 3460.4 and 3363.5 stretching), 1624.3 cm-1 (NH2 in plane deformation)”
Garbacz 和 Wesolowski - 2018 - DSC, FTIR and Raman Spectroscopy Coupled with Mult DOI: 10.3390/molecules23092136
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.