What absorbs at 885 cm⁻¹ in an FTIR spectrum?
A band near 885 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 885 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 |
|---|---|---|---|
| Silicon (Si) | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Silicon hydride | 2 | 2 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Metal oxygen | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Carbon dioxide | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Oxalate | 1 | 1 | 1.0 |
| Silicate | 1 | 1 | 0.9 |
| Carbonate | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
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 885 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
“Figure 2 Magnified view of normalized FTIR absorption spectra of standard compound mixtures cm-1) cm-1) (A) and calcium oxalate stones (B), showing COM (885 and 950 and COD (912 P absorption peaks;”
Quantitative analysis of calcium oxalate hydrate urinary stones using FTIR and 950/912 cm-1 peak ratio DOI: 10.1016/j.vibspec.2019.03.006 -
Silicon (Si) confidence 1.0
“In the spectra, signals attributed to silicon phonons (618 from the silicon cm-1, substrate and small peaks or broad bands at 818, 885 and 1110 cm-1, related to Si-O bonds substrate and small peaks or broad bands at 818, 885 and 1110 relate”
Surface Morphology and Optical Properties of Hafnium Oxide Thin Films Produced by Magnetron Sputtering DOI: 10.3390/ma16155331 -
Alkyl C-H confidence 1.0
“On the other hand, similar bands were observed at 937 885 cm-1, cm-1 743 and 1455 in iRoot, representing C-H stretching.”
Assiry 等 - 2023 - Microstructural and Elemental Characterization of DOI: 10.3390/app13074517 -
Phosphate (PO4) confidence 1.0
“cm-1) cm-1 stretching at 1745 and polyphosphates (P=O stretching 1251 at and P-O-P cm-1) stretching at 885 (Figure 3).”
Calcium Affects Polyphosphate and Lipid Accumulation in Mucoromycota Fungi DOI: 10.3390/jof7040300 -
Phosphate (PO4) confidence 1.0
“-CH bending 2 >CH 723 rocking 2 P=O Polyphosphates 1263 stretching 885 P-O-P stretching”
Metal and Phosphate Ions Show Remarkable Influence on the Biomass Production and Lipid Accumulation in Oleaginous Mucor circinelloides DOI: 10.3390/jof6040260 -
Silicon (Si) confidence 1.0
“The absorption peak centered 885 can be assigned to the bending vibrational modes of Si-H and (Si-H 2) complexes [22].”
Growth of Hydrogenated Nano-crystalline Silicon (nc-Si:H) Films by Plasma Enhanced Chemical Vapor Deposition (PE-CVD) DOI: 10.1016/j.egypro.2017.03.104 -
Silicon (Si) confidence 1.0
“The absorption bands at 885, 650 and 585 are observed only on the IR spectra of rice husk ash (RHA) correspond to the Si-OH and/or Al-OH, Si-O or Al-O and Al-O symmetric stretching vibration and Al-O vibrations respectively.”
Lancellotti 等 - 2015 - Geopolymers An option for the valorization of inc DOI: 10.1016/j.ceramint.2014.10.008 -
Carbon dioxide confidence 1.0
“Partial absorption of calcite is contributed by three intramolecular pressures of carbon dioxide in atmospheric air affect the 885cm-1 (V = 1484, V = 706, V = recarbonationofdecarbonizedACS,whereaspartialpressure and ), three translator 3 4”
Loy 等 - 2016 - Effects of Calcination on the Crystallography and DOI: 10.1155/2016/2914368
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