What absorbs at 985 cm⁻¹ in an FTIR spectrum?
A band near 985 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 985 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 |
|---|---|---|---|
| Carbohydrate | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| Borate | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 1 | 0.9 |
| Nucleic acid | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Sulfonate | 1 | 1 | 1.0 |
| Nitrate | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 0.9 |
| C c single bond | 1 | 0 | 1.0 |
| Methyl | 1 | 0 | 1.0 |
| Alkyl C-H | 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 |
|---|---|---|---|
| chitosan | 985, 1650, 1655 | Methacrylate, C-O single bond, Methoxy (OCH3) | 1 |
| ZnO | 985, 1400, 3430 | Methacrylate, C-O single bond, Methoxy (OCH3) | 1 |
| iron oxide | 985, 1130, 891 | Methoxy (OCH3), Methacrylate, C-O single bond | 1 |
| SiO2 | 985, 1739, 699 | Methoxy (OCH3) | 1 |
| graphene oxide | 985, 1150, 3400 | Methacrylate, C-O single bond, Methoxy (OCH3) | 1 |
| GO | 985, 1720, 1182 | Methacrylate, C-O single bond, 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 985 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
-
Borate confidence 1.0
“O-B-O popular polymer hosts, and they have been most extensively symmetric stretching of at 985 studied for various applications [4].”
Electrical and structural studies of a LiBOB-based gel polymer electrolyte DOI: 10.1007/s11581-016-1834-7 -
Silicon (Si) confidence 1.0
“In the Si-O stretching region of trioctahedralsheet.Thestructuralmisfitbetweenthetetrahedral chrysotileanewbandwasrevealedat985cm¡1,besidesabsorptions and octahedral units causes a curvature, which explains the cm¡1.”
Modification of Chrysotile Surface by Organosilanes: An IR–Photoacoustic Spectroscopy Study DOI: 10.1006/jcis.2001.7524 -
Nitrate confidence 1.0
“The appearance of a small band at 985 is assigned to the presence of a nitrate group (justified by previous work done by Hwang et al., 2014).”
Yadav 等 - 2020 - A novel synthesis and characterization of polyhedr DOI: 10.1016/j.eti.2020.101089 -
confidence 1.0
“In addition, cm-1 the three weak bands located at 669, 887 and 985 are attributable to the Zn-OH the three weak bands located at 669, 887 and 985 cm-1 are attributable to the Zn-OH group”
Rapid Bio-Assisted Synthesis and Magnetic Behavior of Zinc Oxide/Carbon Nanoparticles DOI: 10.3390/cryst13071081 -
Sulfonate confidence 1.0
“The and 985 cm-1 can be assigned to the asymmetric and symmetric stretching of SO3.”
Anis 等 - 2023 - Studies on Polybenzimidazole and Methanesulfonate DOI: 10.3390/polym15132821 -
confidence 1.0
“The intensity of these bands, comparatively to those corresponding to the silica matrix with Si-O-Si framework cm-1, ( vibration (Si-O)) between 985 and 1160 is representative of the high density of organic parts in the as hybrid materials”
Besnard 等 - 2018 - Ion extraction applications of bilayer-structured DOI: 10.1039/c8qm00022k -
Acetate confidence 1.0
“cm-1 cm-1 cm-1 1253 and 1062 (anti-symmetric stretching of the C-O-C bridge), 1018 and cm-1 Ch 985 (skeletal vibrations involving the C-O stretching).”
Physicochemical Properties and Functional Characteristics of Ecologically Extracted Shrimp Chitosans with Different Organic Acids during Demineralization Step DOI: 10.3390/molecules27238285 -
confidence 1.0
“trum of the prepared SiO from rice husk waste is given in Figure 2a, the distinctive bands 2 of the prepared SiO2 from rice husk waste is given in Figure 2a, the distinctive bands of of the SiO network, D1 and D2, can be observed, which are”
Sustainable Remedy Waste to Generate SiO2 Functionalized on Graphene Oxide for Removal of U(VI) Ions DOI: 10.3390/su14052699
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