What absorbs at 1512 cm⁻¹ in an FTIR spectrum?
A band near 1512 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 1512 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 | 13 | 13 | 1.0 |
| Lignin | 9 | 9 | 1.0 |
| Alkyl C-H | 7 | 6 | 1.0 |
| N h | 7 | 6 | 1.0 |
| Alkene (C=C) | 6 | 6 | 1.0 |
| Ring structure | 6 | 5 | 1.0 |
| Amide | 6 | 5 | 1.0 |
| Methacrylate | 4 | 3 | 1.0 |
| Acetate | 4 | 3 | 1.0 |
| Carbonyl (C=O) | 4 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 2 | 1.0 |
| Secondary amine | 3 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| Ketone | 2 | 1 | 1.0 |
| Ester | 2 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Amino acid | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 1512 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
-
Alkyl C-H confidence 1.0
“(-CH bending) and 1512.19cm-1 1604.77 (C=C aromatic ring) [7].”
Cahyono 等 - 2018 - Characteristics of eugenol loaded chitosan-tripoly DOI: 10.1088/1757-899X/349/1/012010 -
Aromatic ring confidence 1.0
“cm-1 Absorption at 1512 was attributed to aromatic asymmetric stretching (C=C) from lignin [9].”
Kuthi 和 Badri - 2014 - Effect of Cooking Temperature on the Crystallinity DOI: 10.1063/1.4895240 -
Carbonyl (C=O) confidence 1.0
“A band at 1709 indicates the presence of Compared to the Bs-ex sample, the BP sample includes two cm-1 extraabsorptionpeaksat1463and1512cm-1,buttheabsorption carbonyl groups.”
Enzymatic Browning in Wheat Kernels Produces Symptom of Black Point Caused by Bipolaris sorokiniana DOI: 10.3389/fmicb.2020.526266 -
Alkene (C=C) confidence 1.0
“cm-1 cm-1 weak band at 1608 and one medium band at 1512 , due to C=C stretching band of T cm-1 lignin which is slightly widened in this region.”
Rout 等 - 2017 - A green approach to produce silver nano particles DOI: 10.1016/j.surfin.2017.03.004 -
Aromatic ring confidence 1.0
“(C shows the absorption bands at 1512, 1381 and cm-1 corresponds to the phenyl nucleus, 2954 3) group and -CH group in the indane >C(CH”
Surender 等 - 2014 - Bismaleimide and Bispropargyl Ether Blends Curing DOI: 10.1134/S1560090414050157 -
confidence 1.0
“Although the spectrum was slightly + from the amide II vibrations (NH band CN stretch of contaminated with non-heme iron signals as typically seen cm-1 cm-1 backbone amide), and the negative peak at 1512 arising from the His ligands by a ne”
Takahashi 等 - 2007 - Water molecules coupled to the redox-active tyrosi DOI: 10.1021/bi701752d -
Lignin confidence 1.0
“cated by considerable decreases in the intensities of the When exposed to the natural elements (e.g., sunlight, air, cm-1 characteristic aromatic lignin peak at 1512 and water), the surface of bamboo culm appears to undergo and other comple”
Wang 和 Ren - 2009 - Surface deterioration of moso bamboo (Phyllostachy DOI: 10.1007/s10086-008-0994-0 -
Aromatic ring confidence 1.0
“The absorption peak at 1512 is related to the stretching vibrations of the aromatic skeleton C=C [35], which characterizes both the chemical structure of lignin and of the isocyanate used (TDI).”
Synthesis and Characterizations of Eco-Friendly Organosolv Lignin-Based Polyurethane Coating Films for the Coating Industry DOI: 10.3390/polym14030416
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