What absorbs at 2110 cm⁻¹ in an FTIR spectrum?
A band near 2110 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 2110 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 | 3 | 3 | 1.0 |
| Silicon hydride | 2 | 2 | 1.0 |
| Adsorbed carbon monoxide | 2 | 0 | 1.0 |
| N h | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Carbon dioxide | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 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 |
|---|---|---|---|
| activated carbon | 2110, 1575, 1210 | 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 2110 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
-
Silicon (Si) confidence 1.0
“The band at 2110 corresponds to stretching vibrations of Si-H bonds [44,45].”
Mechanical properties, chemical analysis and evaluation of antimicrobial response of Si-DLC coatings fabricated on AISI 316 LVM substrate by a multi-target DC-RF magnetron sputtering method for potential biomedical applications DOI: 10.1016/j.apsusc.2017.03.223 -
Alkyl C-H confidence 1.0
“cm-1) The acetylenic C≡C bond stretching (2110 and acetylenic ≡C-H bond stretching (3293 peaks of 2-ethynylpyridine monomer were not seen in the FT-IR spectrum of polymer.”
Gal 等 - 2016 - Synthesis and Characterization of a Water-Soluble DOI: 10.12693/APhysPolA.129.642 -
C=n confidence 1.0
“at 2110 and 2136 These peaks are related to sym10% metrical and asymmetrical stretching of carbodiimide group (R-N=C=N-R), formed in the polymerization process [30, 31].”
New thermal study of polymerization and degradation kinetics of methylene diphenyl diisocyanate DOI: 10.1007/s10973-018-7211-1 -
Hydroxyl (O-H) confidence 1.0
“3300 (O-H stretching), 2110”
FTIR spectroscopy as a unified method for simultaneous analysis of intra- and extracellular metabolites in high-throughput screening of microbial bioprocesses DOI: 10.1186/s12934-017-0817-3 -
Silicon hydride confidence 1.0
“The SiH stretching vibration can be observed at ~2081 SiH stretching vibration at ~2110”
Kralik 和 Kopani - 2023 - Analysis of porous silicon structures using FTIR a DOI: 10.2478/jee-2023-0028 -
Carbonate confidence 1.0
“oxygen vacancies particularly above 100 Thus, during cm-1) as well as bands in phase bands of CO (2110 and 2170 CO oxidation (i.e., in the presence of an excess of O 2) only cm-1 1000-1650 the region, attributed to various carbonate minute”
Lukashuk 等 - 2018 - Operando Insights into CO Oxidation on Cobalt Oxid DOI: 10.1021/acscatal.8b01237 -
Carbon dioxide confidence 1.0
“A clear surface plasmon resonance (SPR) was corresponded to asymmetric O=C=O stretching of CO 2, while the weak band at 2110 cm-1 formed within 5 min resulting in 418 nm of wavelength in the UV-Vis spectrum (Figure 2).”
Endophytic Bacteria Enterobacter hormaechei Fabricated Silver Nanoparticles and Their Antimicrobial Activity DOI: 10.3390/pharmaceutics13040511 -
C c single bond confidence 1.0
“The cm-1 for analyzing raw waste tire pyrolysis char and activated carbon band at 2110 can be attributed to the - C C - stretch in the cm-1 produced by chemical activation with KOH.”
Rutto 等 - 2019 - Adsorption of lead ions onto chemically activated DOI: 10.24425/aep.2019.130245
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.