What absorbs at 1105 cm⁻¹ in an FTIR spectrum?
A band near 1105 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 1105 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 |
|---|---|---|---|
| C-O single bond | 11 | 11 | 1.0 |
| Methoxy (OCH3) | 9 | 9 | 1.0 |
| Methacrylate | 9 | 9 | 1.0 |
| Acetate | 9 | 9 | 1.0 |
| Silicon-oxygen (Si-O) | 8 | 8 | 1.0 |
| Hydroxyl (O-H) | 5 | 4 | 1.0 |
| Silicon (Si) | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Carbohydrate | 4 | 4 | 1.0 |
| Siloxane (Si-O-Si) | 3 | 3 | 1.0 |
| Phosphate (PO4) | 3 | 2 | 1.0 |
| N h | 3 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Lignin | 2 | 2 | 1.0 |
| Ring structure | 2 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 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 |
|---|---|---|---|
| silica | 1105, 1100, 1080 | Methacrylate, Acetate | 1 |
| SiO2 | 1105, 1739, 699 | Methoxy (OCH3) | 1 |
| polyaniline | 1105, 1565, 1570 | Methacrylate, Acetate | 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 1105 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
-
C-O single bond confidence 1.0
“1017-1029cm-1 Peak of ether group (-C-O-C-) at 1105cm-1 (Figure 2) became intense while peak at became almost a plateau due to overlapping peaks contributed by the”
Daud 等 - 2014 - An Investigation on the Properties of Palm-Based P DOI: 10.1155/2014/326716 -
confidence 1.0
“It is on intermediate particles were obtained by arresting the reactions interesting to note that the absorbance values of the Si-O-C University with the addition of acetone at different time schedules TEOS22,23 cm21 stretching bands of at”
De 等 - 2000 - Hydrolysis-condensation reactions of TEOS in the p DOI: 10.1039/B003221M -
confidence 1.0
“FTIR results highlight the characteristic absorption of Si-O-C group at peak 1105 and in both fluorochemical acids, demonstrating that molecules have been successfully coated onto silica nanoparticles.”
Ganie 等 - 2020 - Synthesis and Characterization of a New Surface-Mo DOI: 10.1155/2020/8814260 -
confidence 1.0
“Explicit assignment in text”
Conversion of Sewage Water into H2 Gas Fuel Using Hexagonal Nanosheets of the Polyaniline-Assisted Deposition of PbI2 as a Nanocomposite Photocathode with the Theoretical Qualitative Ab-Initio Calculation of the H2O Splitting DOI: 10.3390/polym14112148 -
confidence 1.0
“that position of Si-O antisymmetric stretching band remains (1105cm(cid:3)1), steady however, the position of Si-O symmetric cm(cid:3)1 stretching band slightly moved from 804 for pure silica to 812cm(cid:3)1 in the case of physical mixture”
Jonynaite 等 - 2010 - Spectroscopic analysis of blue cobalt smalt pigmen DOI: 10.1016/j.vibspec.2009.12.005 -
Acetate confidence 1.0
“O stretching of ether linkage for lignin (Rosa et al., 2012) 1242 - - - - C 1158 1159 1160 1159 1159 Antisymmetric bridge C O C stretching (glycosidic ring) 1105 1105 1105 1106 C O/C C stretching vibration for ring 1103 1053 1053 1054 C O/C”
Kasyapi 等 - 2013 - Bionanowhiskers from jute Preparation and charact DOI: 10.1016/j.carbpol.2012.10.021 -
Alkyl C-H confidence 1.0
“+ C-C 1135 unclear 1135 unclear 1134 1134 1136 stretching stretching C-O + C-H 1105 unclear 1107 unclear 1108 1106 1115 stretching rocking (+) (+) C-O 1070 1094 1070 1095 1086 1081 1082 stretching”
Maeda - 2001 - IR spectroscopic study on the hydration and the ph DOI: 10.1021/la001346q -
confidence 1.0
“cm-1 was attributed to HfSiO, and at ≈880 was assigned to Absorption peak, indicated at ≈1105 was assigned to interstitial oxygen in the Si bulk [3, 27].”
Pandey 等 - 2016 - Impact of post deposition annealing in O-2 ambient DOI: 10.1016/j.optmat.2014.08.005
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