What absorbs at 800 cm⁻¹ in an FTIR spectrum?
A band near 800 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 800 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
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 |
|---|---|---|---|
| SiO2 | 800, 1739, 699 | Silicon-oxygen (Si-O), Alkyl C-H, Silicon (Si) | 1 |
| hydroxyapatite | 800, 1620, 1639 | 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 800 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
“B-C bond at 2,800 cm-1, representing the content of boron impurity in the diamond [39].”
Morphology and FTIR Characteristics of the Alluvial Diamond from the Yangtze Craton, China DOI: 10.3390/cryst12040539 -
Silicon (Si) confidence 1.0
“However, the observed 〈…〉 Here, the notation implies that the corresponding arithmetic cm-1 weak peak at around 800 can be assigned to the symmetric mean should be subtracted like Si-O-Si vibrations.”
Cetin 等 - 2011 - Chemical bonding structure of TiO2 thin films grow DOI: 10.1016/j.tsf.2011.04.021 -
Phosphate (PO4) confidence 1.0
“6 also shows the average IR spectra of the carbonate and 1200cm-1 phosphate bands between 800 and for the calcified calcifieddepositsoftendonandmusclesamples(Fig.6).Ithasbeen reportedthatapeaknear1020cm-1isattributedtothe(cid:2) sample depo”
Chiou 等 - 2011 - FT-IR microscopic imaging of calcified deposit of DOI: 10.1016/j.vibspec.2011.06.004 -
Silicon (Si) confidence 1.0
“The absorption peaks for the asymmetric vibration of Si-O bonds in the structure of SiO 2-NCC (Figure cm-1 cm-1 1c) appeared at 1068 while a peak at 800 was attributed to the vibration of Si-OH.”
Nanocellulose-silica polyethersulfone hybrid composite stabilized lipase for esterification DOI: 10.1063/1.5125521 -
Water (H2O) confidence 1.0
“Some water content in the chars (Table 3) seems to be due to the absorption of air moisture 800◦”
Georgakopoulos 等 - 2003 - Study of low rank Greek coals using FTIR spectrosc DOI: 10.1080/00908310390232442 -
confidence 1.0
“mainly characterized by the presence of two absorption peaks in the region from 600 to cm-1: cm-1 1700 a strong and wide peak at 1100 assigned to stretching vibrations of the cm-1 Si-O bond and a weak wide peak at 800 assigned to the bendin”
Kadikova 等 - 2020 - Glass depolymerization in the process of long-term DOI: 10.1002/jrs.5305. -
confidence 1.0
“cm-1 asymmetric stretch around 1300 Furthermore, a sharp peak around 800 shows O-C-O cm-1 asymmetric vibration, while a sharp peak around 500 corresponds to Co-O stretch vibration, as”
Khunur 等 - 2020 - Thiocyanate Doping in Gel-Growth Cobalt Oxalate Cr DOI: 10.1088/1757-899X/833/1/012017 -
Boron nitrogen confidence 1.0
“The FTIR spectrum exhibited absorption bands at cm-1, approximately 800 and 1378 which were related to the h-BN structure.”
Kim 等 - 2015 - One-Pot Synthesis of h-BN Fullerenes Usinsg a Grap DOI: 10.1007/s12540-015-5043-0
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