What absorbs at 1399 cm⁻¹ in an FTIR spectrum?
A band near 1399 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 1399 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 |
|---|---|---|---|
| Methacrylate | 4 | 3 | 1.0 |
| Acetate | 4 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 2 | 1.0 |
| C-O single bond | 3 | 2 | 1.0 |
| Carbonate | 2 | 2 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Nitrile | 1 | 1 | 1.0 |
| Water (H2O) | 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 |
|---|---|---|---|
| ZnO | 1399, 1400, 3430 | Alkyl C-H, Acetate, Methacrylate | 1 |
| graphene | 1399, 1720, 2097 | Methacrylate, Acetate, Carboxyl (COOH) | 1 |
| zinc oxide nanoparticles | 1399, 1744, 1627 | Acetate, Alkyl C-H, Methacrylate | 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 1399 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
“Several peaks with values at 1457 cm-1, 1399 cm-1, or 1340 cm-1 can also be seen, associated with the presence of CO3.”
Remineralization Potential of Three Restorative Glass Ionomer Cements: An In Vitro Study DOI: 10.3390/jcm12062434 -
Carboxyl (COOH) confidence 1.0
“The strong characteristic absorption peak at 1550 was attributed to to the vibration of COOgroup of the galacturonic acid and those at 1399 cm-1 could correspond to COOcm-1 the vibration of group of the galacturonic acid and those at 1399 c”
Lukova 等 - 2020 - Prebiotic Activity of Polyand Oligosaccharides O DOI: 10.3390/app10082648 -
confidence 1.0
“ligands, these bands were shifted to 1512 and 1398 cm-1 for Zn[(acac)(LPhe)H2O] (Figure These phenomena caused a change in electron distribution, which resulted in a chemical 5a) and to 1518 and 1399 cm-1 for Zn[(acac)(LTrp)H2O] (Figure 5b)”
Synthesis of the Bacteriostatic Poly(l-Lactide) by Using Zinc (II)[(acac)(L)H2O] (L = Aminoacid-Based Chelate Ligands) as an Effective ROP Initiator DOI: 10.3390/ijms22136950 -
C-O single bond confidence 1.0
“The GO spectrum presents a broad band at 3192 cm-1, corresponding to the O-H stretching vibration, and peaks associated to the C = O (1734 cm-1), C-OH (1399 cm-1), C-O-C (1207 cm-1) and C-O (977 cm-1) vibrations.”
Joining Caffeic Acid and Hydrothermal Treatment to Produce Environmentally Benign Highly Reduced Graphene Oxide DOI: 10.3390/nano11030732 -
Acetate confidence 1.0
“The peaks at 1399 were attributed to the stretching vibrations of few C-O bond (v C-O) and cm(cid:16)1 C-C bond (v C-C).”
Dong 等 - 2012 - Preparation and properties of Nd,YbGGG polycrysta DOI: 10.1007/s40145-012-0030-0 -
Nitrile confidence 1.0
“The colored solution which could be due to the nitrile triple bond 1633.21cm-1 (DM) has been precisely prepared by mixing the three dyes C≡N, a band at which originates from the 1398.56cm-1 with same proportion in ultrapure water.”
Fegousse 等 - 2019 - Pineapple Bark Performance in Dyes Adsorption Opt DOI: 10.1155/2019/3017163 -
Alkyl C-H confidence 1.0
“commonlyusedmethodforparticlessizedistributionincolloidal The peak at 1399 refers to C-H stretching vibrations of the solution.”
Gupta 等 - 2018 - Effective Antimicrobial Activity o Green ZnO Nano DOI: 10.3389/fmicb.2018.02030 -
Acetate confidence 1.0
“The characteristic bands at 1720 and 1399 cm-1 were assigned to the stretching vibrations C=O and the bonding of C-OH of GO (curve a), respectively [1].”
Facile Construction of Functionalized GO Nanocomposites with Enhanced Antibacterial Activity DOI: 10.3390/nano9070913
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