What absorbs at 860 cm⁻¹ in an FTIR spectrum?
A band near 860 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 860 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 | 10 | 10 | 1.0 |
| Methoxy (OCH3) | 5 | 4 | 1.0 |
| Methacrylate | 5 | 4 | 1.0 |
| C-O single bond | 5 | 4 | 1.0 |
| Acetate | 5 | 4 | 1.0 |
| Metal oxygen | 4 | 4 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Silicon (Si) | 3 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Aldehyde (CHO) | 3 | 3 | 0.9 |
| Aromatic ring | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Silicate | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 0.8 |
| Carbonate | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 860 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
-
Acetate confidence 1.0
“Two additional peaks unique to triethylene glycol (960-905 and 905cm21) were also compared to the peak area of the amide 860 III region to determine the accuracy of using the C-O stretches of TEG to determine relative changes in TEG content”
Changes in hydrogen bonding in protein plasticized with triethylene glycol DOI: 10.1002/app.42166 -
Metal oxygen confidence 1.0
“Band ascribed to Ti-O-Ti chains formation”
Fast responsive anatase nanoparticles coated fiber optic pH sensor DOI: 10.1016/j.jallcom.2020.156246 -
confidence 1.0
“X-Ray diffraction patterns showed that crystallization occurs by calcination above 973 A characteristic Raman peak at 860 cm-', assigned to the stretching vibration of short Ti-0 bonds, increased in intensity with increasing 0' irradiation”
Kohno 等 - 1996 - Preparation of BaTi4O9 by a sol-gel method and its DOI: 10.1039/JM9960601921 -
Alkyl C-H confidence 1.0
“In addition to the three dom- (DNA, RNA and of polysaccharides) (Sano et al., 2016), and 860cm-1 C-H inating classes, the rest microbes at class level were most abundant in (aromatic bending vibration) (Huang et al., 2014).”
Fast start-up strategies of MBBR for mariculture wastewater treatment DOI: 10.1016/j.jenvman.2019.109267 -
Acetate confidence 1.0
“The peaks occurring at 1164 cm in bambara starches may be 338 attributed to coupling mode of C-O and C-C stretching, while peaks at 860 and 928 could be 339 attributed to C-O stretching.”
Physicochemical properties of starches with variable amylose contents extracted from bambara groundnut genotypes DOI: 10.1016/j.carbpol.2015.06.100 -
Phosphate (PO4) confidence 1.0
“Conformational changes were ascribed to bands at 860, 837, and 805 Our results consistently demonstrate the ability of asymmetric and symmetric phosphate vibrations in thin films to show significant band reshaping and intensity changes with”
Serec 等 - 2021 - Conformational Transitions of Double-Stranded DNA DOI: 10.3390/app11052360 -
confidence 1.0
“vibrations of NiO6 and LiO6 octahedral units in the region 400 - 700 Moreover, FTIR cm-1 spectra for all the samples show peaks at 860 and 1430 associated with Ni-O bond.”
Taha 和 El-Molla - 2020 - Green simple preparation of LiNiO2 nanopowder for DOI: 10.1016/j.jmrt.2020.04.098 -
Hydroxyl (O-H) confidence 1.0
“There was a co-existence of OH stretching (at 860”
Tangwiwat 和 Milne - 2005 - Barium titanate sols prepared by a diol-based sol- DOI: 10.1016/j.jnoncrysol.2004.12.008
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