What absorbs at 871 cm⁻¹ in an FTIR spectrum?
A band near 871 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 871 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 | 5 | 5 | 1.0 |
| Phosphate (PO4) | 3 | 3 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.9 |
| Ester | 1 | 1 | 0.7 |
| Methoxy (OCH3) | 1 | 0 | 1.0 |
| Methacrylate | 1 | 0 | 1.0 |
| C-O single bond | 1 | 0 | 1.0 |
| Acetate | 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 |
|---|---|---|---|
| zinc oxide | 871, 1627, 1638 | Alkyl C-H | 1 |
| LDPE | 871, 1720, 1737 | Alkyl C-H | 1 |
| chitosan | 871, 1650, 1655 | Alkyl C-H | 1 |
| chitin | 871, 1650, 1655 | Alkyl C-H | 1 |
| calcium phosphate | 871, 1070, 1149 | Phosphate (PO4), Alkyl C-H | 1 |
| zinc oxide nanoparticles | 871, 1744, 1627 | 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 871 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
“The band at 871 is due to essential oil (phytol), and flavanoids (varinging, quercitrin, asymmetrical and symmetrical stretching of zinc carhesperitin, and kaempferol).”
Biosynthesis of zinc oxide nanoparticles using leaf extract of Calotropis gigantea: characterization and its evaluation on tree seedling growth in nursery stage DOI: 10.1007/s13204-017-0586-7 -
N h confidence 1.0
“Among them, 711, 871 and 872 cm-1 indicate -NH out of plane bending for chitosan and ring stretching (Fig.”
Sudatta 等 - 2020 - Extraction, characterization and antimicrobial act DOI: 10.1016/j.ijbiomac.2020.06.291 -
C c single bond confidence 1.0
“The band at 871 is C C backbone stretchcm-1 [v(C ing vibration COO)] [31].”
Sun 等 - 2012 - Effect of polymerization with paraformaldehyde on DOI: 10.1016/j.tca.2012.03.015 -
Phosphate (PO4) confidence 1.0
“peak (vibration P-O) at 1037 and the carbonates' peaks at 871 and 1621 The main difference was the LDPEBAGSRO 20/30 showed a slightly higher intensity phosphate peak compared to LDPEBAGSRO 30/20.”
Bioactivity, cytocompatibility and thermal properties of experimental Bioglass-reinforced composites as potential root-canal filling materials DOI: 10.1016/j.jmbbm.2017.01.022 -
Alkyl C-H confidence 1.0
“The weak bands at 871, 784, and 550 can be assigned cm(cid:2)1 to the CH rocking.”
Synthesis, crystal structure, and characterization of cyclohexylammonium tetraisothiocyanatocobaltate(II): A single-source precursor for cobalt sulfide and oxide nanostructures DOI: 10.1016/j.heliyon.2019. -
Phosphate (PO4) confidence 1.0
“tions which, relative to calcium, are compatible with The anion (HPO shows an IR band at 871”
SEM-EDX micro-analysis and FTIR infrared microscopy by ATR of a bladder stone from the IIIth millennium BC from the B1S passage-grave of the necropolis in Chenon (Charente, France) DOI: 10.5802/crchim.143 -
Silicon (Si) confidence 1.0
“The bands at 664 (S-1) and 871 cm-1 and 671 (S-28) probably correspond to Si-O-Si bending vibrations inside of silica chains 42SO bending vibrations.”
Colovic 等 - 2013 - Creating of Highly Active Calcium-Silicate Phases DOI: 10.2298/SOS1303341C -
C c single bond confidence 1.0
“cm1 (HCH and OCH in plane bending), 1319 (CH2 rocking vibration at C6), 1253 1 cm-1 cm-1 (G ring stretching), 1157 (C-O-C asymmetrical stretching), 1029 (C-C, Ccm-1 (COC,CCO and CCH deformation OH, C-H ring and side group vibrations), 871 c”
Iordache 等 - 2018 - FT-IR ANALYSIS OF FUSARIUM OXYSPORUM GROWN MYCO-CO DOI: 10.24264/icams-2018.VIII.8
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