What absorbs at 1168 cm⁻¹ in an FTIR spectrum?
A band near 1168 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 1168 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 |
|---|---|---|---|
| Methacrylate | 13 | 12 | 1.0 |
| Acetate | 13 | 12 | 1.0 |
| Methoxy (OCH3) | 11 | 10 | 1.0 |
| C-O single bond | 9 | 8 | 1.0 |
| Alkyl C-H | 8 | 7 | 1.0 |
| Ester | 5 | 5 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Carbonyl (C=O) | 4 | 4 | 1.0 |
| Ketone | 3 | 3 | 1.0 |
| Methyl | 3 | 3 | 1.0 |
| Amine primary | 2 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.9 |
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 |
|---|---|---|---|
| Silver Nanoparticles | 1168, 1636, 1631 | Methacrylate, Acetate, C-O single bond | 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 1168 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
“In the heparin-modified sample, there are peaks around 1168 cm-1 and 1240 cm-1, which correspond to the S-O and S=O bands.”
Surface Heparinization of a Magnesium-Based Alloy: A Comparison Study of Aminopropyltriethoxysilane (APTES) and Polyamidoamine (PAMAM) Dendrimers DOI: 10.3390/jfb13040296 -
Amine primary confidence 1.0
“The FTIR spectrum revealed two adsorption peaks at 3442 and 3199 cm-1, which linked to the characteristic bands of S-H and N-H groups, whereas Figure 5c demonstrates characteristic malachite surface NH2, C-H, C=O, C-O-C and C-S peaks at app”
Ibrahim 等 - 2022 - Effect of Ammonium Sulfide on Sulfidization Flotat DOI: 10.3390/min12101193 -
confidence 1.0
“retinal HOOP 959 951 959 C-C 1166,b 1202b retinal stretching 1168, 1202 1192 N-H bendingc Schiff base 1254 1301 1249”
Maeda 等 - 1999 - Chromophore-protein-water interactions in the L in DOI: 10.1021/bi9907072 -
Amine primary confidence 1.0
“The band at 1168 The spectroscopic region 1840-950 of each specis due to -NH 2 trum was exported as an Excel file.”
Pappas 等 - 2008 - Identification and differentiation of goat and she DOI: 10.1016/j.foodchem.2007.07.034 -
confidence 1.0
“3 cm-1, transition metal tested that was capable of generating Brønsted The immediate disappearance of IR peaks at 1168 which acidity, yields different results.”
Pena 等 - 2004 - Identification of surface species on titania-suppo DOI: 10.1021/jp0313122 -
Acetate confidence 1.0
“In the synchronous C-O spectra of both film types, the strongest autopeak corresponded to the stretching mode, appearing at1151and1168cm-1fortheLBandspin-coatedfilms,respectively.Thissuggeststhattheconformation of the tert-butoxy group chan”
Shin 等 - 2002 - Structural comparison of Langmuir-Blodgett and spi DOI: 10.1021/la020135d -
Amide confidence 1.0
“The peak near 1168 indicates the C-N stretch1.20x10-2 cm-1”
In-Situ Chemical Synthesis, Microstructural, Morphological and Charge Transport Studies of Polypyrrole-CuS Hybrid Nanocomposites DOI: 10.1007/s10904-020-01747-8 -
Acetate confidence 1.0
“1167.81cm-1), 1102.98cm-1), 4th values of and alcohol (C-O stretch, and alkyl instars larvae had 36.68/60.95μg/mL.”
Baranitharan 等 - 2022 - Fabrication of Silver Nanoparticles Using Fimbrist DOI: 10.1155/2022/4083663
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