What absorbs at 1250 cm⁻¹ in an FTIR spectrum?
A band near 1250 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 |
|---|---|---|---|
| C-O single bond | 8 | 8 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Sulfate (SO4) | 3 | 3 | 0.9 |
| Phosphate (PO4) | 3 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 0.9 |
| Oxygen heterocycle | 2 | 2 | 0.8 |
| Siloxane (Si-O-Si) | 2 | 1 | 0.9 |
| Silicon (Si) | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 0.9 |
| Amine primary | 1 | 1 | 0.9 |
| C n single bond | 1 | 1 | 0.9 |
| Carbohydrate | 1 | 1 | 0.9 |
| S eq o | 1 | 1 | 0.9 |
| Aromatic ring | 1 | 1 | 0.8 |
| Carbonate | 1 | 1 | 0.7 |
| Metal oxygen | 1 | 1 | 0.7 |
| Lignin | 1 | 1 | 0.7 |
| Silicon carbon | 1 | 0 | 0.7 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“cm-1, cm-1, cm-1, cm-1, cm-1 cm-1 most of the band located at 1250 1320 1360 1398 1435 and 1465 are attributed to twisting (CH 2) , stretching (CH 2), symmetric CH wagging , asymmetric(CH 2) wagging, s 2 a”
Arya 和 Sharma - 2018 - Structural, microstructural and electrochemical pr DOI: 10.1007/s11581-017-2364-7). -
Alkyl C-H confidence 1.0
“Strong peak at 1250 cm-1 assigned to C-H stretching vibrations of chemisorbed hydrogen.”
Misra 等 - 2006 - FTIR studies of nitrogen doped carbon nanotubes DOI: 10.1016/j.diamond.2005.08.013 -
Alkyl C-H confidence 1.0
“Strong peak at 1250 cm-1 consistent with C-H.”
Misra 等 - 2007 - FTIR spectroscopy of multiwalled carbon nanotubes DOI: 10.1166/jnn.2007.723 -
Hydroxyl (O-H) confidence 1.0
“explicit assignment in text”
Anacleto 等 - 2018 - Evaluation of physicochemical properties as suppor DOI: 10.1016/j.jpha.2018.01.001 -
confidence 1.0
“band located at 1250 assigned to B-C and C=N bonds”
Jalaly 等 - 2017 - A novel, simple and rapid route to the synthesis o DOI: 10.1038/s41598-017-03794-7 -
Amide confidence 1.0
“Explicit assignment: 'III (1250 cm-1)'”
Sun 等 - 2020 - Effects of SCCO2, Gamma Irradiation, and Sodium Do DOI: 10.3390/ijms21051565 -
Amide confidence 1.0
“Explicit assignment: 'amide III band, at about 1250'”
Tombolesi 等 - 2022 - Early cardiac-chamber-specific fingerprints in hea DOI: 10.1038/s41598-022-07390-2 -
confidence 1.0
“Characteristic of phosphoryl group (ν(P=O)).”
Tumurbaatar 等 - 2022 - CO2 Adsorption on the Nand P-Modified Mesoporous DOI: 10.3390/nano12071224
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