What absorbs at 743 cm⁻¹ in an FTIR spectrum?
A band near 743 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 |
|---|---|---|---|
| Metal oxygen | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Amide | 2 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Methacrylate | 1 | 0 | 1.0 |
| Ketone | 1 | 0 | 1.0 |
| Ester | 1 | 0 | 1.0 |
| Carboxyl (COOH) | 1 | 0 | 1.0 |
| Carbonyl (C=O) | 1 | 0 | 1.0 |
| Acetate | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
confidence 1.0
“RIP Fourier Transmission Infra-Red spectroscopy (FTIR) and it is found that the important peaks cm-1 cm-1 were appeared at 490 due to the benzenoid ring stretching vibration, 1562 for C cm-1 quinoid ring vibration and 743 corresponds to the”
Antistatic and Dielectric properties of one-dimensional Al2+:Nd2O3 nanowire doped polyaniline nanocomposites for electronic application DOI: 10.1016/j.sna.2018.07.018 -
N n bond confidence 1.0
“cm(cid:2)1 cm(cid:2)1 The strong absorbance peaks at 743 and 970 can be assigned to the symmetric and asymmetric vibration modes of vibrations.23,29 n n s(P-O-P) and as(P-O-P) stretching This corresponds to the formation of PO tetrahedral c”
High proton conductivity of NaMg1−xLixHx (PO3)3·yH2O with a three-dimensional open framework in the intermediate temperature range DOI: 10.1039/d1ma00592h -
Metal oxygen confidence 1.0
“the same situations that the absorption band between 743 cm(cid:0) VO3(cid:0) 1 Ti-O of the BiVO4/TiO2 sample is contributed to symmetrical stretching vibrations of in monoclinic BiVO4 and the and 470 4 vibration of TiO2 [23].”
Microstructures, thermal and electric properties of bismuth vanadium oxide (BiVO4) as an anode in electrolysis systems coated with a conductive glass indium thin oxide (ITO) DOI: 10.1016/j.csite.2021.101188 -
Hydroxyl (O-H) confidence 1.0
“Operando spectra collected in contact with ⟶h+ cm-1 218O R-FeIII-OH R-FeIV=O H+ exhibited absorption peaks at 743 and 857 (Fig.”
Determination of photoelectrochemical water oxidation intermediates on haematite electrode surfaces using operando infrared spectroscopy DOI: 10.1038/NCHEM.2557 -
Aromatic ring confidence 1.0
“The spectra of poly (o-chloroaniline) and POC-MMT The characteristic point of phenyl C-N stretching mode appeared at nanocomposites with various load percentages 1,297cm-1, 810cm-1 743cm-1 and the spectrum values at and were (0, 1, 3, 5, 7,”
Iqbal 等 - 2022 - Fabrication of Poly(o-Chloroaniline) to MMT Clay a DOI: 10.3389/fmats.2022.874735 -
Metal oxygen confidence 1.0
“Moreover, sharp cm-1, sharp peaks for the Zr-O group in the monoclinic zirconia are observed at 743 peaks for the Zr-O group in the monoclinic zirconia are observed at 743 cm-1, correspondcorresponding to an increase in the concentration of”
Ponnusamy 等 - 2022 - Synthesis, Structural, and Mechanical Behavior of DOI: 10.3390/ma15082924 -
Aromatic ring confidence 1.0
“The small peaks at 1072, 1122 and 1272 were small peak at 1599 cm-1 was attributed to the aromatic ring, and C-H and C-R bending modes were cm´1 due to C-O groups, and the weak peak at 743 was attributed to aromatic =C-H bending.”
Microcapsules Filled with a Palm Oil-Based Alkyd as Healing Agent for Epoxy Matrix DOI: 10.3390/polym8040125 -
confidence 0.8
“Downward shift to 743 cm-1 reveals uncoordinated or free TFSI anion.”
Liew 等 - 2016 - Poly(Acrylic acid)-Based Hybrid Inorganic-Organic DOI: 10.3390/polym8050179
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