What absorbs at 1251 cm⁻¹ in an FTIR spectrum?
A band near 1251 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Methacrylate | 6 | 6 | 1.0 |
| Acetate | 6 | 6 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Amide | 3 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.8 |
| Phosphorus | 1 | 0 | 1.0 |
| Nitrogen heterocycle | 1 | 0 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
confidence 1.0
“The moderate cm-1 belongs to N-H stretching absorption peak at 1251”
In-doped ZnS nanoparticles: structural, morphological, optical and antibacterial properties DOI: 10.1007/s00339-021-04425-9 -
Borate confidence 1.0
“cm-1 *1251 The band centered at is attributed to B-O The resulted IR data were used in this research in order to stretching vibrations in [BO 3] units from boroxol cm-1”
Rada 等 - 2009 - Structural and electronic properties of tellurite DOI: 10.1007/s10853-009-3433-8 -
Acetate confidence 1.0
“cm-1 C-O stretching 1251 cm-1”
Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films DOI: 10.1208/s12249-020-01811-z -
Oxygen heterocycle confidence 1.0
“For spectrum, the main peaks located at 1251 and 877 LENR cm-1 are assigned for symmetric and asymmetric stretching of epoxide ring, respectively.”
Azhar 等 - 2017 - Epoxidation and Hydroxylation of Liquid Natural Ru DOI: 10.17576/jsm-2017-4603-17 -
Amide confidence 1.0
“resents another alternative by accurately quantifying ligand The maximum amide peaking at 1653, 1546 and 1251 cm-1 density, but such techniques require matrix digestion [50].”
Boulet-Audet 等 - 2015 - Cleaning-in-place of immunoaffinity resins monitor DOI: 10.1007/s00216-015-8871-3) -
Acetate confidence 1.0
“the C-O-C peaks of the ester bond at 1251 and cm-1 1024 also confirm this.”
Synthesis and Application of Tackifying Dispersant Poly (Vinyl Alcohol-Acrylic Acid-Triallyl Cyanate) DOI: 10.3390/polym14030557 -
Phosphate (PO4) confidence 1.0
“Furthermore, an cm-1) ester bond in the FTIR spectra (C=O stretching at 1745 was selected for the estimation cm-1) of lipids and a phosphate functional group bond (P=O stretching at 1251 was selected for the estimation of polyphosphates.”
Calcium Affects Polyphosphate and Lipid Accumulation in Mucoromycota Fungi DOI: 10.3390/jof7040300 -
Acetate confidence 1.0
“(b) (c) and The main vibrations, where the greatest changes in the wood occurred, were identified at the peaks at 1251 cm-1, which is related to the C-O stretching vibration;”
Moya 等 - 2022 - In Situ Synthesis of Fe3O4 Nanoparticles and Wood DOI: 10.3390/ma15093394
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