What absorbs at 1450 cm⁻¹ in an FTIR spectrum?
A band near 1450 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 1450 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 | 85 | 81 | 1.0 |
| Amide | 27 | 24 | 1.0 |
| Methacrylate | 21 | 21 | 1.0 |
| Acetate | 21 | 21 | 1.0 |
| Methoxy (OCH3) | 18 | 18 | 1.0 |
| Aromatic ring | 16 | 16 | 1.0 |
| C-O single bond | 12 | 12 | 1.0 |
| Methyl | 12 | 12 | 1.0 |
| Ring structure | 11 | 11 | 1.0 |
| N h | 11 | 10 | 1.0 |
| Carboxyl (COOH) | 11 | 10 | 1.0 |
| Carbonate | 11 | 10 | 1.0 |
| Alkene (C=C) | 10 | 10 | 1.0 |
| Hydroxyl (O-H) | 9 | 8 | 1.0 |
| Water (H2O) | 8 | 6 | 1.0 |
| Secondary amine | 7 | 7 | 1.0 |
| C n single bond | 7 | 7 | 1.0 |
| Protein | 6 | 6 | 1.0 |
| C c single bond | 6 | 5 | 1.0 |
| Lipid | 4 | 4 | 1.0 |
| Carbonyl (C=O) | 4 | 4 | 1.0 |
| Ester | 4 | 4 | 1.0 |
| Amino acid | 4 | 4 | 1.0 |
| Nitrogen heterocycle | 3 | 3 | 1.0 |
| Lignin | 3 | 3 | 1.0 |
| Carbohydrate | 3 | 3 | 1.0 |
| Ketone | 3 | 3 | 1.0 |
| N-O bond | 3 | 3 | 1.0 |
| Urea | 2 | 2 | 1.0 |
| Ammonium | 2 | 2 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Bromine | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Styrene | 1 | 1 | 1.0 |
| Lewis acid site | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 0.8 |
| Amine primary | 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 |
|---|---|---|---|
| LDPE | 1450, 1720, 1737 | Alkyl C-H, Methacrylate, Acetate | 1 |
| lignin | 1450, 1035, 1510 | 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 1450 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
“The maximum concentrations of C-defects the data and factors mentioned above, the diamond crystal about 1 Р N+ 10Ni at.% at = defects are,respectively, 370 reach 290 at.ppm,and those of A and carat in weight was grown using metal solvent Fe”
Distribution of H1a-centers in as-grown diamonds of Fe-Ni-C system: FTIR-mapping study DOI: 10.1016/j.diamond.2016.07.001 -
confidence 1.0
“in final form, March 10, 2016 cm-1 Abstract-The IR-peak 1450 (H1a-center) associated with nitrogen interstitials have been studied in nitrogen-bearing diamonds synthesized at high parameters in the Fe-Ni-C system.”
Babich 等 - 2016 - Manifestation of nitrogen interstitials in synthet DOI: 10.1134/S0016702916100025 -
Alkyl C-H confidence 1.0
“the band at approximately 1450 resulting from the 900 Salmonella (Enteritidis ODA 993058113, Heidelberg ODA C-H 00469325, Kentucky ODA 008267, and Typhimurium ODA 99389631, deformation bending of in the >CH groups and the band 2 cm-1 Muench”
Baldauf 等 - 2007 - Effect of selective growth media on the differenti DOI: 10.1016/j.mimet.2006.06.012 -
Water (H2O) confidence 1.0
“∼1450 band at We chose this band because the region is cm-1 affected ∼1640 not by the varying water absorption at modes).39 (in-plane bending This normalization was never more than a few percent and yet was necessary because the films”
Chan 和 Bogomolni - 2012 - Structural Water Cluster As a Possible Proton Acce DOI: 10.1021/jp304934t -
Acetate confidence 1.0
“At low wavenumber, the peak at cm-1 cm-1 1450 corresponds to both CH3 and CH2 bending vibration and at 1378 for C-H bending vibration.”
Dahham 等 - 2018 - The Influences of Zirconium Dioxide on ENR-25ZrO2 DOI: 10.1088/1742-6596/1019/1/012055 -
Lignin confidence 1.0
“content.[13,22-24] hydroxyl From these chemical data changes we can possibly conclude about assigning the Chemical analysis of native lignin sambandnear1490cm(cid:1)1tophenolicringvibraple (lignin in wood) showed that it has 66 cm(cid:1)1 t”
Derkacheva 和 Sukhov - 2008 - Investigation of lignins by FTIR spectroscopy DOI: 10.1002/masy.200850507 -
Alkyl C-H confidence 1.0
“Explicit assignment: 'near 1450 were formed due to the long chain of C-H (bending vibration)'”
Biodegradation of Unpretreated Low-Density Polyethylene (LDPE) by Stenotrophomonas sp. and Achromobacter sp., Isolated From Waste Dumpsite and Drilling Fluid DOI: 10.3389/fmicb.2020.603210 -
Alkene (C=C) confidence 1.0
“1643 C=C stretching 1450 ± 20 1448 1455 1457”
Differentiation between copal and amber by their structure and thermal behaviour DOI: 10.1007/s10973-023-12333-8
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