What absorbs at 1084 cm⁻¹ in an FTIR spectrum?
A band near 1084 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 1084 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 | 14 | 13 | 1.0 |
| Acetate | 14 | 13 | 1.0 |
| Methoxy (OCH3) | 13 | 12 | 1.0 |
| C-O single bond | 13 | 12 | 1.0 |
| Phosphate (PO4) | 5 | 4 | 1.0 |
| Silicon-oxygen (Si-O) | 5 | 4 | 1.0 |
| Nucleic acid | 4 | 3 | 1.0 |
| Protein | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Phosphorus | 3 | 2 | 1.0 |
| Carbohydrate | 3 | 2 | 1.0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| C n single bond | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Nitro (NO2) | 1 | 1 | 1.0 |
| Borate | 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 |
|---|---|---|---|
| chitosan | 1084, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 1 |
| collagen | 1084, 1408, 1660 | Methacrylate, Acetate, Methoxy (OCH3) | 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 1084 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
-
Phosphate (PO4) confidence 1.0
“The vibration around 1232 is assigned to PO antisymmetric stretching of cm-1 2phosphodiesters while the vibration ~1084 is assigned to PO symmetric stretching of phosphodiesters.”
Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan DOI: 10.1016/j.vibspec.2019.04.005 -
Borate confidence 1.0
“FTIR spectrum is dominated by the characteristic peak for cm-1 B-P ∼811 vibration mode located at with a shoulder at cm-1 ∼850 B-O-B along with other peaks related to cm-1 ∼1084 B-O-H δ-bond stretching mode at and located cm-1.”
Dalui 等 - 2008 - Boron phosphide films prepared by co-evaporation t DOI: 10.1016/j.tsf.2007.09.047 -
Acetate confidence 1.0
“C-O C-O 1089 stretching 1157 stretching C-O C-O 987 stretching 1084 stretching Table 2 The Particle Size by XRD of Chemically Synthesized C-O”
El Bialy 等 - 2020 - Comparative Toxicological Effects of Biologically DOI: 10.2147/IJN.S241922 -
Acetate confidence 1.0
“III are, respectively, located at 1640, 1534 and 1240 The chitosan-specific bands located at cm´1 cm´1 1026 (stretching of C-O) and 1084 (of OH) were higher on the collagen membranes coated with 1% chitosan;”
Chitosan-Coated Collagen Membranes Promote Chondrocyte Adhesion, Growth, and Interleukin-6 Secretion DOI: 10.3390/ma8115413 -
Acetate confidence 1.0
“distillation the peaks located at 1084 and 1045 (bonds from C-O of the ethanol molecule) were less intense in comparison to these same peaks observed 3.4 FTIR analysis of the tequila distillation”
Mondragon-Cortez 等 - 2022 - Application of Fourier transform infrared spectros DOI: 10.24275/rmiq/Alim2806 -
Amide confidence 1.0
“With respect to DNA, the absorption bands related to the PO symmetric stretching vibrational mode 2 cm-1) were considered, because this bond is abundant in this macromolecule in the same way that (1084 cm-1) C-N and C-C stretchings (1120 ar”
Mostaco-Guidolin 等 - 2010 - Molecular and chemical characterization by Fourier DOI: 10.3233/SPE-2010-0466 -
Acetate confidence 1.0
“∼707, inpurevaterite 873, 1413, 2505, 2876, 2983 In the FTIR spectra, cm-1 (υ (υ and common C-O stretching at around 1084 and 713 due to out-of-plane bending 2), the asymmetric stretching 3) and in-”
Nagabhushana 等 - 2009 - Swift heavy ion irradiation induced phase transfor DOI: 10.1016/j.ssc.2009.07.049 -
Nitro (NO2) confidence 1.0
“were present in both FTIR spectra of plant extract and FeNPs, such as alkyl halides, alkynes, aromatics and aliphatic amines, esters, ethers, alcohol, carboxylic acids, and nitro Nanomaterials2022,12,2404 11of25 compounds with peaks at 526.”
Green Synthesis and Characterization of Iron Nanoparticles Synthesized from Aqueous Leaf Extract of Vitex leucoxylon and Its Biomedical Applications DOI: 10.3390/nano12142404
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