What absorbs at 1100 cm⁻¹ in an FTIR spectrum?
A band near 1100 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 1100 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 |
|---|---|---|---|
| PET | 1100, 1408, 800 | Methacrylate, Acetate, Methoxy (OCH3) | 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 1100 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
“The main molecular stretching of the CH group and CH bending, 2 2 cm-1 respectively, whereas peaks at 1100 and 960 were”
Awal 等 - 2012 - Thermal analysis and spectroscopic studies of elec DOI: 10.1007/s10973-011-1875-0 -
Boron nitrogen confidence 1.0
“LLM confirmed rule peak-group candidate”
Bejarano 等 - 2006 - Deposition of B4CBCNc-BN multilayered thin films DOI: 10.1016/j.tsf.2005.08.192 -
Acetate confidence 1.0
“cm-1 and the peak at 1100 is due to C-O group [32].”
Structural and optical characteristics of Ti-doped ZnO nanorods deposited by simple chemical bath deposition DOI: 10.1007/s10854-017-6905-7 -
confidence 1.0
“847cm-1, (1635cm-1), 470-481cm-1, hygroscopic water Si-O vibrations 1100, 611-621, etc.”
Cai 等 - 2007 - A Fourier transform infrared spectroscopic study o DOI: 10.1016/j.saa.2006.02.053 -
Boron nitrogen confidence 1.0
“Well-defined peaks at cm-1, 1100 and 1387 corresponding to the 2 (out-plane bending of B-N-B bond) h-BN 787 (in-plane stretching vibration mode, the F2 (stretching) c-BN Transversal Optical (TO) mode and the E of B-N bond) vibration mode of”
Cubic and hexagonal boron-nitride (c-BN/h-BN) thin films deposited in situ by r.f. magnetron sputtering DOI: 10.1002/pssb.200461776 -
Silicon (Si) confidence 1.0
“1100cm-1 The IR absorbance at around corresponds to asymSi-O-Si metric stretching vibrations [15].”
Cetin 等 - 2011 - Chemical bonding structure of TiO2 thin films grow DOI: 10.1016/j.tsf.2011.04.021 -
Ring structure confidence 1.0
“4, 2018 ET OF species.-The Effect of foreign effect of various species such pyridinium ring and shows the presence of an IR peak around 1100cm-1,whichoverlapswiththeanalyticalpeakofperchlorate.”
Chandrawanshi 等 - 2018 - Collective Ion-Pair Single-Drop Microextraction At DOI: 10.5740/jaoacint.17-0188 -
Acetate confidence 1.0
“PET exhibited its characteristic cm-1, due to the stretching of the ester bands at 1740 cm-1, belonging to the carbonyl group, and at 1100 C-O-C stretching of the bond.”
Cohn 和 Stern - 2000 - Sequential surface derivatization of PET films DOI: 10.1021/ma9900784
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