What absorbs at 873 cm⁻¹ in an FTIR spectrum?
A band near 873 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 873 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 |
|---|---|---|---|
| Carbonate | 15 | 14 | 1.0 |
| C-O single bond | 8 | 8 | 1.0 |
| Methoxy (OCH3) | 7 | 7 | 1.0 |
| Methacrylate | 7 | 7 | 1.0 |
| Acetate | 7 | 7 | 1.0 |
| Silicon-oxygen (Si-O) | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Aromatic ring | 4 | 3 | 1.0 |
| Metal oxygen | 3 | 1 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Metal oxo | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Phosphate (PO4) | 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 |
|---|---|---|---|
| Nanotubes | 873, 1735, 1630 | Methacrylate, Methoxy (OCH3) | 1 |
| calcium carbonate | 873, 3232, 2954 | Carbonate, C-O single bond, Methoxy (OCH3) | 1 |
| montmorillonite | 873, 1637, 523 | Methacrylate | 1 |
| bentonite | 873, 882, 918 | Carbonate | 1 |
| hydroxyapatite | 873, 1620, 1639 | Methacrylate, Carbonate | 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 873 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
“Thus, the most important requirements of vibration of the hydroxyl group whereas the peaks at 43(cid:1) cm(cid:1)1 cm(cid:1)1 molecular miscibility and homogeneity of the PC/n-HA was .19 1093 and 603 belong to PO In the composite, 42(cid:1)”
Banerjee 和 Balasubramanian - 2015 - Nanotexturing of PCn-HA nanocomposites by innovat DOI: 10.1039/c4ra15488f -
Acetate confidence 1.0
“The FTIR spectrum of pure calcium carbonate shows the cm(cid:2)1, presence of a strong band centered around 1453 characteristics of the C-O stretching mode of carbonate cm(cid:2)1 together with a narrow band around 873 of the”
Boke 等 - 2004 - Quantification of CaCO3-CaSO3 center dot 0.5H(2)O- DOI: 10.1016/j.matlet.2003.07.008 -
Amide confidence 1.0
“Several IR peaks near 3367 (OH and/or NH pinkcolorofnon-calcifiedtissue.Fig.4showstheFT-IRabsorbance stretching of 2 images representing the areas under the IR peaks at 1034 and proteinand/orlipid),2930or2928(CHstretchingofproteinand/or 873”
Chiou 等 - 2011 - FT-IR microscopic imaging of calcified deposit of DOI: 10.1016/j.vibspec.2011.06.004 -
Ring structure confidence 1.0
“The epoxide ring absorption took place at 873 cm-1 and 1250 cm-1.”
Potency of Urea-Treated Halloysite Nanotubes for the Simultaneous Boosting of Mechanical Properties and Crystallization of Epoxidized Natural Rubber Composites DOI: 10.3390/polym13183068 -
Hydroxyl (O-H) confidence 1.0
“The absorption peaks at 873 cm-1, which correspond to inner surface and outer surface hydroxyl groups stretching, cm-1, which correspond to inner surface and outer surface hydroxyl groups stretching, cm-1 and 1250 indicated the epoxide ring”
Selectively Etched Halloysite Nanotubes as Performance Booster of Epoxidized Natural Rubber Composites DOI: 10.3390/polym13203536 -
Carbonate confidence 1.0
“The band located at 873 related carbonate vibrations (ν 2, CO that are characteristic of B-type CHAp[3].”
Wati 和 Yusuf - 2019 - Carbonated Hydroxyapatite Derived from Cerastoderm DOI: 10.1088/1757-899X/546/4/042049 -
Carbonate confidence 1.0
“Formation of calcite is also responsible for the appearance of the 873 band due to the out-of-plane deformation mode of carbonate anion.”
Rehydration Driven Na-Activation of Bentonite—Evolution of the Clay Structure and Composition DOI: 10.3390/ma14247622 -
Acetate confidence 1.0
“had lower intensities in the spectra of the NS10 and SF10 in these Similar to the stretching vibrations, the cm-1 specimens compared to the OPC and FA10 samples after bending-in-plane vibrations of the C-O bonds at 873”
Biricik 和 Sarier - 2014 - Comparative Study of the Characteristics of Nano S DOI: 10.1590/S1516-14392014005000054
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