What absorbs at 843 cm⁻¹ in an FTIR spectrum?
A band near 843 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 |
|---|---|---|---|
| Alkyl C-H | 4 | 3 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| Silicon carbon | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Secondary amine confidence 1.0
“at 500-700 vibration of a dye band S-O and S=O at 1022 and 1250 In addition, the bands at cm-1 cm-1 843 and 831 are derived from the vibration of the primary and secondary amine groups of the dye”
Studies of the potential of a native natural biosorbent for the elimination of an anionic textile dye Cibacron Blue in aqueous solution DOI: 10.1038/s41598-021-88657-y -
Alkyl C-H confidence 1.0
“After completely washing sponds to the C-O in PMMA structure while bending with distilled water, ethanol, absolute ethanol to remove vibrations of C-H exhibited absorption at 843, 914, and 986 hydrazine, sodium, and chlorine ion, the sample”
Hussain 等 - 2017 - Surfactant Incorporated Co Nanoparticles Polymer C DOI: 10.1155/2017/7191590 -
Acetate confidence 1.0
“cm-1): ν, FTIR (KBr, 3038 (=C-H stretch of the aromatic rings), 2933-2851 (C-H stretch of aliphatic chains), 1627 (-N=CHstretch), 1601, 1587, 1511 (C-C ring stretch), 1243, 1H-NMR 1163 (C-O-Cstretch), 843 (absorption band assigned to 1,4-ph”
Mesomorphic Behavior of Symmetric Azomethine Dimers Containing Different Chromophore Groups DOI: 10.3390/molecules26082183 -
C-O single bond confidence 1.0
“Sulfate-associated vibrations of carrageegroups in carrageenan can be found in the region from 900 to 1200 namely, at cm-1 cm-1 920 (C-O stretching in 3,6-anhydro-D-galactose), 1035 and 1063 (C-O and (D-galactose-4-sulphate), 1225 nan can a”
Edible Films from Carrageenan/Orange Essential Oil/Trehalose—Structure, Optical Properties, and Antimicrobial Activity DOI: 10.3390/polym13030332 -
Silicon (Si) confidence 1.0
“Si-CH3 group vibrations were assigned to the absorbance signals at 865 cm-1 and 843 cm-1.”
A Process Analytical Concept for In-Line FTIR Monitoring of Polysiloxane Formation DOI: 10.3390/polym12112473 -
Water (H2O) confidence 1.0
“The presence of cm-1, coordinated water was confirmed by the medium strength bands at 843 characteristic of rocking H 2O ( H 2O) frequencies [31,32].”
Zangaro 等 - 2019 - Study of the thermal behavior in oxidative and pyr DOI: 10.1016/j.jorganchem.2005.11.058. -
Oxygen heterocycle confidence 0.9
“Text states oxirane peaks (doublet) at 825 and 843 cm-1.”
Derahman 等 - 2019 - EPOXIDATION OF JATROPHA METHYL ESTERS VIA ACIDIC I DOI: 10.1590/0104-6632.20190362s20180326 -
Alkyl C-H confidence 0.9
“Explicit assignment in text.”
Glass Powder Additive on Recycled Polypropylene Filaments: A Sustainable Material in 3D Printing DOI: 10.3390/polym14010005
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