What absorbs at 1694 cm⁻¹ in an FTIR spectrum?
A band near 1694 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 1694 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.
可能性のある官能基アサイン
| 官能基 | 裏付け事実 | 引用元 | 最高信頼度 |
|---|---|---|---|
| Amide | 5 | 3 | 1.0 |
| Carbonyl (C=O) | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Protein beta turn | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| N-O bond | 1 | 0 | 1.0 |
| Urethane | 1 | 0 | 1.0 |
ランキングは蓄積された文献証拠を反映しており、単一の権威あるルールではありません。常にサンプルのコンテキストと照合して確認してください。
Possible materials
| 素材 | 補助ピーク | Overlapping groups | 引用元 |
|---|---|---|---|
| chitosan | 1694, 1650, 1655 | Amide, Hydroxyl (O-H) | 1 |
| protein | 1694, 1650, 1640 | Amide, Carbonyl (C=O), Carboxyl (COOH) | 1 |
| magnetite | 1694, 1740, 1263 | Hydroxyl (O-H), Carboxyl (COOH) | 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 1694 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.
これらのアサインの根拠となる文献
-
Hydroxyl (O-H) 信頼度 1.0
“Peak of TLE was broad and strong occurred at 3261 as -OH group vibration, 1694 as max cm-1 cm-1 C=O group, 1359 as -NH group, and 1056 as C-O group.”
A facile method for green synthesis of Nd2O3 nanoparticles using aqueous extract of Terminalia catappa leaf DOI: 10.1063/1.5064090 -
Alkyl C-H 信頼度 1.0
“The absorption peak located at 232 cm-1 cm-1 1694 corresponds to C =O stretching of alkanes.”
Antibacterial, antibiofilm and cytotoxic effects of Nigella sativa essential oil coated gold nanoparticles DOI: 10.1016/j.micpath.2015.11.021 -
Acetate 信頼度 1.0
“In the absorption spectrum of the C=O stretching (1694 which indicates the oxidation”
Potential effects of nano-cellulose and nano-silica/polyvinyl alcohol nanocomposites in the strengthening of dyed paper manuscripts with madder: an experimental study DOI: 10.1038/s41598-022-23907-1 -
Protein 信頼度 1.0
“was also found, of lower intensity 1628 cm-1 II band around 1545 cm-1 (Figure 1 and Figure cal of protein aggregates, and by the upshift of and broader compared to the prefixation stage, 2 A,B,C), the absorption of proteins dominates the 16”
Ami 等 - 2014 - Role of water in chromosome spreading and swelling DOI: 10.4081/ejh.2014.2330 -
Carboxyl (COOH) 信頼度 1.0
“of the methyl and methylene group at 2880 and 2935 cm-1 The sharp band at 1694 assigns to stretching vibration The saturated adsorbent with oil was filtered in a vacuum (C = O) of carboxylic acid.”
Eco-friendly adsorbents based on abietic acid, boswellic acid, and chitosan/magnetite for removing waste oil from the surface of the water DOI: 10.1007/s11356-022-20169-2 -
Protein alpha helix 信頼度 1.0
“(β-sheets), (α-helix/ Teknoloji peaks at 1694 tion proteins during Similar results were also 1680 (turn/loop), 1647 cm-1 (α-helix)”
Guler 等 - 2019 - Characterization of CD133(+)CD44(+) human prostat DOI: 10.1039/c9an00093c -
Hydroxyl (O-H) 信頼度 1.0
“1 the vibrational peaks of MnO found at 1694 1533 1385 987 2 cm1 cm1 corresponds to -OH bending vibrations complexed with Mn atoms and those around 684 and”
Helen 等 - 2023 - Amelioration of ionic conductivity (303 K) with th DOI: 10.21203/rs.3.rs-1557220/v1 -
Amide 信頼度 1.0
“Particularly, a down-shift from 1666 shifts to For Xano bound spectra we also amide-I 1656cm-1 7cm-1 1694cm-1 Asn4046.52 to observed a of amide-I band upon binding of ACh points to an up shift in signal to and”
Vibrational spectroscopy analysis of ligand efficacy in human M2 muscarinic acetylcholine receptor (M2R) DOI: 10.1038/s42003-021-02836-1
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