What absorbs at 878 cm⁻¹ in an FTIR spectrum?
A band near 878 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 878 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 | 6 | 6 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Silicon-oxygen (Si-O) | 4 | 4 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| C c single bond | 2 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Silicon hydride | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 0.9 |
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 |
|---|---|---|---|
| nanotube | 878, 1540, 1080 | Alkyl C-H, C-O single bond | 1 |
| clay | 878, 1736, 2855 | Silicon-oxygen (Si-O), Alkyl C-H | 1 |
| PVDF | 878, 1160, 840 | Alkyl C-H | 1 |
| Fe2O3 | 878, 1130, 1631 | 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 878 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
-
Alkyl C-H confidence 1.0
“Absorption bands around RIPT cm-1 878 corresponds to CF=CH vibration of FU.”
Covalent diphenylalanine peptide nanotube conjugated to folic acid/magnetic nanoparticles for anti-cancer drug delivery DOI: 10.1016/j.jddst.2017.06.005 -
confidence 1.0
“2016) while a couple of bands at 878 and 708 are C due to stretching vibrations of Ag-O-Ag bond (Vanaja et al.”
Haq 等 - 2018 - Fabrication of pure and moxifloxacin functionalize DOI: 10.1016/j.jphotobiol.2018.07.011 -
Acetate confidence 1.0
“The absorption band near 878 cm-1 is caused cm-1 at 1437 is assigned to the symmetric stretching of C-O bonds [31], suggesting that by the bending vibration of CO32- [29,30] and the absorption band at 1437 cm-1 is assigned cm-1 cm-1”
Preparation and Characterization of Low-Carbon Cementitious Materials Based on Soda-Residue-Activated Ground Granulated Blast-Furnace Slag: A Case Study on Cemented Paste Backfills DOI: 10.3390/met -
Silicon (Si) confidence 1.0
“at approximately 878 This new band is likely associated with (Si-O-Ce) stretching vibrations resulting from the bond formation between the cerium and silicon atoms from”
Enhanced Coating Protection of C-Steel Using Polystyrene Clay Nanocomposite Impregnated with Inhibitors DOI: 10.3390/polym15020372 -
Fluorine (C-F) confidence 1.0
“bending L ibrary on 878 878 CC and CF symmetric stretching 881 [19] α PVDF 2 [19/12/2022].”
Chipara 等 - 2020 - Spectroscopic investigations on PVDF-Fe2O3 nanocom DOI: 10.1002/app.48907 -
confidence 1.0
“The bands at 955 cm-1 cm-1 (S-1) and 966 (S-28) belong to Si-O lattice vibrations, while the bans at 878 (S-1)”
Colovic 等 - 2013 - Creating of Highly Active Calcium-Silicate Phases DOI: 10.2298/SOS1303341C -
Silicon hydride confidence 1.0
“1080 1077 1066 [18] stretching SiH bending 878 880 881 [19] SiH wagging 660 670 674 [20] out H2 and silicon (n-type (100)) for FTIR and EDAX measure-”
Coyopol 等 - 2012 - Optical and Structural Properties of Silicon Nanoc DOI: 10.1155/2012/368268 -
Alkyl C-H confidence 1.0
“cm1 The band at 878 (figure 4a) is due to CH rocking mode [38].”
Interaction of (3-Aminopropyl)triethoxysilane With Late Ar-N 2 Afterglow: Application to Nanoparticles Synthesis DOI: 10.1002/ppap.201500201
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