What absorbs at 1407 cm⁻¹ in an FTIR spectrum?
A band near 1407 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 1407 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 |
|---|---|---|---|
| Carboxyl (COOH) | 7 | 7 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Carbonate | 5 | 5 | 1.0 |
| Alkyl C-H | 5 | 4 | 1.0 |
| Carbonyl (C=O) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Methyl | 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 |
|---|---|---|---|
| PET | 1407, 1408, 800 | Alkyl C-H, Amide | 1 |
| graphene | 1407, 1720, 2097 | Amide, Carboxyl (COOH) | 1 |
| DNA | 1407, 1712, 1660 | Amide | 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 1407 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
-
Carboxyl (COOH) confidence 1.0
“The cm-1 ω ω contribution of the idealized carboxylate vibrations to the = = 1407 is inhomogeneously diagonal peak 1 3 normal modes of EDTA and the metal complexes for broadened, stretches along the diagonal, and has an elliptical”
CH Mode Mixing Determines the Band Shape of the Carboxylate Symmetric Stretch in Apo-EDTA, Ca2+–EDTA, and Mg2+–EDTA DOI: 10.1021/acs.jpca.1c03061 -
Carboxyl (COOH) confidence 1.0
“of carboxylic groups after oxidation steps was confirmed withthepeaksat1719cm-1 and1407cm-1 ,whichcorrespond 3.2.”
Abdelhalim 等 - 2016 - Graphene Functionalization by 1,6-Diaminohexane an DOI: 10.1155/2016/1485280 -
C c single bond confidence 1.0
“LLM confirmed rule peak-group candidate”
Al Dine 等 - 2019 - Self-Limited Grafting of Sub-Monolayers via Diels- DOI: 10.1021/acsomega.9b02391 -
Carbonate confidence 1.0
“The next maximum, located at 1407 cm-1 was attributed to carbonate band stretching and”
Simultaneous FTIR and Raman Spectroscopy in Endometrial Atypical Hyperplasia and Cancer DOI: 10.3390/ijms21144828 -
Alkene (C=C) confidence 1.0
“Furthermore, shifts in the peak positions at 1407, 1328, 1050, and cm-1, 750 which are characteristic of C=C stretching, C-H stretching, C-O bending, and C-Clstretching, respectively, werealsorecordedafterCPEadsorption.”
Robust Magnetic -Fe2O3/Al–ZnO Adsorbent for Chlorpyriphos Removal in Water DOI: 10.3390/w14071160 -
Carbonate confidence 1.0
“The weak bands at 1407 and 1458 and its combination, cm-1 cmand overtone bands observed at 2997, 2938 and 2880 (S-1) and 2990, 2938 and 2872 1 cm-1 (S-28) and week vibrations at 1407 and 1414 indicate the presence of carbonate species cm-1”
Colovic 等 - 2013 - Creating of Highly Active Calcium-Silicate Phases DOI: 10.2298/SOS1303341C -
Carbonyl (C=O) confidence 1.0
“Specifically, cm-1 the 2960 band was attributed to the aliphatic C-H symmetrical bond stretching, cm-1 cm-1 C-O 1712 to the ester carbonyl bond stretching, 1407 for stretching of the cm-1”
Use of Fourier-Transform Infrared Spectroscopy for DNA Identification on Recycled PET Composite Substrate DOI: 10.3390/app12094371 -
Acetate confidence 1.0
“cm-1 cm-1 The 1718 sharp peak represents C=O stretching vibration, 1407 the aromatic Polymers2021,13,1077 7of12”
The Use of Laminates of Commercially Available Fabrics for Anti-Stab Body-Armor DOI: 10.3390/polym13071077
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