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Formation Of Iron(VI) In Ozonalysis Of Iron(III) In Alkaline Solution

Mossbauer spectrum of Fe(VI) frozen solution in 5M NaOH (77 K)Formation of iron(VI) in ozonalysis of iron(III) in alkaline solution. Perfiliev Y.D., Benko E.M., Pankratov D.A., Sharma V.K., Dedushenko S.K. //Inorganica Chimica Acta. 2007. V.360. №8. P.2789-2791.Search the full text below. Ищи полный текст ниже.

Here we report the formation of iron in hexavalent state, FeVIO42- in ozonalysis of iron(III) in alkaline medium. The formation of tetrahedral FeVIO42- ion is confirmed by UV–Visible and Mössbauer spectroscopic techniques. The value of isomer shift - δ, of the tetraoxyanion is consistent with known δ values for various salts of iron(VI) ion.

Iron is the most abundant transition element on Earth and commonly exists in compounds of its +2 and +3 oxidation states. Iron ions in these two oxidation states are generally used in biological electron transfer processes. Iron in higher oxidation states such as +4, +5, and +6 are involved in iron enzymes, organic synthesis, and Fenton chemistry. Examples include capability of Fe(IV) and Fe(V) at enzymatic sites to abstract H and/or to break C–C bond, participation of high-valent nonheme ironoxo species in biometric oxidations, and involvement of aqua oxoiron(IV) in environmental and catalytic chemistry.


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Mössbauer Diagnostics of the Isomorphic Substitution of Iron for Aluminum in Triclinic Iron Vanadate

Dependence on the fraction of iron atoms in the i-th position in respective surrounding j on the degree of substituting x in AlxFe3 – xV3O12Mössbauer Diagnostics of the Isomorphic Substitution of Iron for Aluminum in Triclinic Iron Vanadate. Pankratov D.A., Yur’ev A.I. //Bulletin of the Russian Academy of Sciences. Physics. 2013. V.77. №6. P.759-764.Search the full text below. Ищи полный текст ниже.

Mössbauer spectroscopy and X-ray powder diffractometry (XRD) phase analysis are used to study mixed vanadates with the composition AlxFe3– xV3O12, where x is 0, 0.3, 1.0, 1.5, 2.0, 2.7 and 3.0. Mössbauer spectroscopy is used to study the distribution of trivalent cations over different crystallographic positions. It is shown that the distribution of aluminum atoms differs from those expected from statistic and thermodynamic models.

Materials based on iron and vanadium compounds, which include material doped by transition or nontransition metals, are widely used as catalysts and sensor materials. Apart from solid solutions, two individual compounds form in the iron(III) oxide–vanadium(V) oxide system in particular: Fe2V4O13 and FeVO4. In turn, iron ortovanadate FeVO4 crystallizes depending on the conditions in an orthorhombic or triclinic system. In addition to its use in catalysis, triclinic iron vanadate has recently attracted attention due to its interesting magnetic properties. The type of iron vanadate formed at normal pressures is a multiferroic, and antiferromagnetic ordering is observed in it at temperatures below 22 K.


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Electron Paramagnetic Resonance Of Ferrite Nanoparticles

EPR spectra of Fe2O3 nanoparticles at different temperature. DH is the peak-to-peak linewidth, A is the EPR signal amplitude. It is presumed that S1 is the superparamagnetic signal (g=2.12) from the g-Fe2O3 phase, S2 is the paramagnetic EPR signal (g=2.02) from magnetically isolated centers in g-Fe2O3, S3 is the rhombic symmetry signal (g=4.3) from the a-Fe2O3 phase.

Electron Paramagnetic Resonance Of Ferrite Nanoparticles. Koksharov Yu.A., Pankratov D.A., Gubin S.P., Kosobudsky I.D., Beltran M., Khodorkovsky Y., Tishin A.M. //Journal of Applied Physics. 2001. V. 89. № 4. P. 2293-2298Search the full text below. Ищи полный текст ниже.

Three types of iron-based oxide nanoparticles (weight compositions Fe2O3, BaFe2O4, and BaFe12O19) embedded in a polyethylene matrix are studied using the electron paramagnetic resonance technique. All nanoparticles are found to be multiphase. Thermal variations of electron paramagnetic resonance spectra reveal the presence of two phases in the Fe2O3 nanoparticles. One such phase undergoes an antiferromagnetic-like transition near 6 K. Nanoparticles of BaFe2O4 demonstrate a resonance anomaly near 125 K that could indicate the presence of a magnetic phase. Reduced magnetic anisotropy in BaFe12O19 nanoparticles may be related to either structural imperfection or particle smallness (effective diameter of less than 10 nm). Our data clearly show that low temperature experiments are desirable for the correct identification of nanoparticles by means of the elecstron paramagnetic resonance technique.


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