What absorbs at 1384 cm⁻¹ in an FTIR spectrum?
A band near 1384 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 1384 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 | 18 | 17 | 1.0 |
| Acetate | 14 | 14 | 1.0 |
| Methacrylate | 13 | 13 | 1.0 |
| Amide | 13 | 13 | 1.0 |
| N-O bond | 12 | 11 | 1.0 |
| Carboxyl (COOH) | 11 | 10 | 1.0 |
| Methoxy (OCH3) | 9 | 9 | 1.0 |
| Nitrate | 8 | 7 | 1.0 |
| Secondary amine | 7 | 7 | 1.0 |
| C n single bond | 7 | 7 | 1.0 |
| C-O single bond | 6 | 6 | 1.0 |
| Methyl | 6 | 6 | 1.0 |
| Hydroxyl (O-H) | 6 | 5 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Carbonyl (C=O) | 5 | 5 | 1.0 |
| Alkene (C=C) | 4 | 4 | 1.0 |
| Ketone | 4 | 4 | 1.0 |
| Ester | 4 | 4 | 1.0 |
| Carbonate | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Sulfate (SO4) | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1.0 |
| N eq o | 2 | 2 | 1.0 |
| Silicon hydride | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Urethane | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 0.9 |
| Nitro (NO2) | 1 | 0 | 0.9 |
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 |
|---|---|---|---|
| humic acid | 1384, 1660, 1220 | Alkyl C-H, Methacrylate, Acetate | 1 |
| copper oxide | 1384, 624, 1686 | Alkyl C-H, Methacrylate, Amide | 1 |
| copper oxide nanoparticles | 1384, 624, 1317 | Alkyl C-H, Methacrylate, Acetate | 1 |
| silver nanoparticles | 1384, 1636, 1631 | Alkyl C-H, Methacrylate, Acetate | 1 |
| hydrogel | 1384, 1632, 1062 | Amide, Methacrylate, Acetate | 1 |
| poly(vinyl alcohol) | 1384, 1700, 2993 | Acetate, Methacrylate, Alkyl C-H | 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 1384 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
“In addition, The crystal structures of the nanocomposites were determined cm(cid:3)1 the bands at 454, 556 and 603 by a Rigaku X-ray diffractometer (XRD) using Cu Ka radiation at could be related to strontium (cid:2) ferritecharacteristicpe”
Evaluation of microwave and magnetic properties of substituted SrFe12O19 and substituted SrFe12O19/multi-walled carbon nanotubes nanocomposites DOI: 10.1016/j.matchemphys.2013.08.045 -
N-O bond confidence 1.0
“In both cases, peaks around cm-1 1384 were observed, which is characteristic of N O and N O stretching of NO 3.”
Antimycotic nail polish based on humic acid‐coated silver nanoparticles for onychomycosis DOI: 10.1002/jctb.6676 -
Carboxyl (COOH) confidence 1.0
“J.Fontetal./AnalyticaChimicaActa598(2007)119-127 123 1384cm-1 pressed on a diamond cell and measurements were taken on one bands are due to carboxylic acids.”
Font 等 - 2007 - Fourier transform infrared spectroscopy as a suita DOI: 10.1016/j.aca.2007.07.021 -
confidence 1.0
“The insertion of fertilizer into hydrogel matrix was sharpen the peaks of hydrogel moieties and led cm-1 to new peak appearance at 1384 (NO moieties), correspond to the interaction with zinc ions.”
Hendrawanh 等 - 2019 - Poly (vinyl alcohol)glutaraldehydePremna oblongi DOI: 10.1088/1757-899X/509/1/012048 -
Acetate confidence 1.0
“The band at 1384 was bond.20 Absorption at ascribed to the C=O planes, respectively, of the tenorite structure of cm(cid:2)1 cm(cid:2)1 and 3478 was ascribed to H-O-H 1623 CuO.”
Kayani 等 - 2015 - Characterization of Copper Oxide Nanoparticles Fab DOI: 10.1007/s11664-015-3867-5 -
N-O bond confidence 1.0
“The next 182 3cm-1 band at 1384 is due to the oscillation in NO groups of the residual La(III) salts 183”
Synthesis of lanthanum tungstate interconnecting nanoparticles by high voltage electrospinning DOI: 10.1016/j.apsusc.2015.05.194 -
Amide confidence 1.0
“Spectral features like very good classification between normal and malignant spectra cm(cid:1)1 broader amide I, and peaks at 1384, 1269, 939 and 854 was observed as shown in Fig.”
Krishna 等 - 2006 - Raman spectroscopy studies for diagnosis of cancer DOI: 10.1016/j.vibspec.2006.01.011 -
Carboxyl (COOH) confidence 1.0
“The negative peak around 1384 corresponding to symmetric carboxylic vibrations, also”
Alteration of Sugar-Induced Conformational Changes of the Melibiose Permease by Mutating Arg141 in Loop 4-5 DOI: 10.1016/j.bpj.2009.03.025
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