What absorbs at 2200 cm⁻¹ in an FTIR spectrum?
A band near 2200 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 2200 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 |
|---|---|---|---|
| Nitrile | 6 | 4 | 1.0 |
| N-O bond | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 4 | 3 | 1.0 |
| Secondary amine | 4 | 1 | 1.0 |
| C n single bond | 4 | 1 | 1.0 |
| Amide | 4 | 1 | 1.0 |
| N h | 3 | 3 | 0.9 |
| Silicon hydride | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| C#c | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 1 | 1.0 |
| Adsorbed carbon monoxide | 2 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Thiocyanate | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbon dioxide | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 0.8 |
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 |
|---|---|---|---|
| soil | 2200, 575, 1240 | Hydroxyl (O-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 2200 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
-
Carbon dioxide confidence 1.0
“Normalized intensity is the integrated area of ing lost their labile compounds prior to sampling, as was 2200cm-1 the CO2 peak from 2400 to normalized to weight of the the case with the analysed POM having been sampled seven sample.”
Demyan 等 - 2013 - Combining a coupled FTIR-EGA system and in situ DR DOI: 10.5194/bg-10-2897-2013 -
Nitrile confidence 1.0
“Nitrile bands at approximately 2200 sp3 were identified in all films.”
Galeano-Osorio 等 - 2014 - Carbon nitride films grown by cathodic vacuum arc DOI: 10.1126/science.245.4920.841 -
N-O bond confidence 1.0
“A.M.Giovannozzi,M.Rocchia/SensorsandActuatorsB130(2008)795-801 797 2250cm-1, no signals at 2200 and due to the Si-H stretching withoxygenatomsinback-bondingconfiguration(O ySiH with x”
Giovannozzi 和 Rocchia - 2008 - Effect of the reaction time, reagent concentration DOI: 10.1016/j.snb.2007.10.043 -
Thiocyanate confidence 1.0
“cm-1 SCN vibration, such as a sharp peak of CN group around 2200 If sharp peak around 2200 was observed, the presence of SCN in the crystal, either as coordinating ligand to cobalt(II) or as counter”
Khunur 等 - 2020 - Thiocyanate Doping in Gel-Growth Cobalt Oxalate Cr DOI: 10.1088/1757-899X/833/1/012017 -
Nitrile confidence 1.0
“It is worth to mention that, in the present study the PPy film growth process in cold plasma polymerization tech- (CBN) cm21 indicates absence of nitrile group band at 2200 nique, the activation of monomers and reactivation of the”
Microstructural, wetting, and dielectric properties of plasma polymerized polypyrrole thin films DOI: 10.1002/app.43982 -
Hydroxyl (O-H) confidence 1.0
“In SY21-31 1470±490µgg-1, tent is with single grains having up the similar height and width of both OH bands lead to an ap2200µgg-1 parent broad single peak.”
Lueder 等 - 2023 - A framework for quantitative in situ evaluation of DOI: 10.5194/ejm-35-243-2023 -
Alkyl C-H confidence 1.0
“The The reaction was continued until the NCO content of the resin mixture plasma treatment oxidizes the methyl groups on the surface-migrated was lower than 5%, which corresponds to an absorbance peak height of 2200cm-1.”
Anchored quaternary ammonium salts adsorbed on polyurethane film surfaces DOI: 10.1016/j.porgcoat.2019.105343 -
C#c confidence 1.0
“cm-1 and 2611.01 >3000 (Medium) Alkane (C-H Stretching) 2715.39 2879.43cm-1 and2868.32cm-1 ±2860cm-1 Alkane(C-HStretching) (Medium) 2210.28cm-1 ±2200cm-1 Alkyne(C≡CStretching) (Medium) cm-1 cm-1 2935.05 ±2935 (Medium) Alkane (C-H Stretching”
Validation of the Developed Zero-Order Infrared Spectrophotometry Method for Qualitative and Quantitative Analyses of Tranexamic Acid in Marketed Tablets DOI: 10.3390/molecules26226985
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