共查询到20条相似文献,搜索用时 15 毫秒
1.
Morsy M. Abou-Sekkina Osama A. Shalma 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):51-57
(Y1.85?U0.15) FeO3 orthoferrite was carefully prepared using the solid-state high temperature ceramic and sintering technique. On this orthoferrite, numerous measurements have been undertaken before and after 1.24 Mrad γ-absorbed dose, namely X-ray diffraction (XRD), DC-electrical conductivity versus temperature, UV/Vis. absorption, IR absorption, Mössbauer effect (ME) and EPR. In the present work the results obtained were explained, interpreted and discussed in details on the basis of lattice structure of the new perovskite investigated and the interaction of γ-radiation with the orthoferrite lattice. 相似文献
2.
Mössbauer parameters of frozen salt solutions could be correlated with apparent degree of dissociation, γ. KSnCl3 and KSnBr3 were dissolved in 0.5 M H2SO4, whereas NH4 SnCl3 was dissolved in 0.5 M HClO4. Mössbauer studies were made at different concentrations. 相似文献
3.
《Journal of Coordination Chemistry》2012,65(6):977-987
The tris(2-chloromethyl-4-oxo-4H-pyran-5-olato-κ2O5,O4)iron(III), [Fe(kaCl)3], has been synthesized and characterized by the crystal structure analysis, magnetic susceptibility measurements, Mössbauer, and EPR spectroscopic methods. The X-ray single crystal analysis of [Fe(kaCl)3] revealed a mer isomer. The magnetic susceptibility measurements indicated the paramagnetic character in the temperature range of 2 K–298 K. The EPR and Mössbauer spectroscopy confirmed the presence of an iron center in a high-spin state. Additionally, the temperature-independent Mössbauer magnetic hyperfine interactions were observed down to 77 K. These interactions may result from spin–spin relaxation due to the interionic Fe3+ distances of 7.386 Å. 相似文献
4.
Compounds of the type M3[Fe(CN)6]2XH2O (M = Co(II), Ni(II), Cu(II), and Zn(II)) were prepared and magnetic properties of their powders were investigated by means of EPR spectra, Mössbauer effect and magnetic susceptibility measurements. The temperature dependence of the magnetization for the complexes Co3[Fe(CN)5]2- 10H2O, Ni3[Fe(CN)6]2-10H2O and Cu3[Fe(CN)6]2-4H2O revealed that below the critical temperatures 15, 22 and 20 K respectively, these complexes have zero-field magnetization. The magnetic hysteresis at 10 K for Co(II), Ni(II) and Cu(II) complexes was observed. Mössbauer spectra at 4.2 K for the compounds are discussed. 相似文献
5.
《Journal of Coordination Chemistry》2012,65(14):1537-1546
Tris(2-hydroxymethyl-4-oxo-4H-pyran-5-olato-κ2O5,O4)iron(III) [Fe(ka)3], has been characterised by magnetic susceptibility measurements Mössbauer and EPR spectroscopy. The crystal structure of [Fe(ka)3] has been determined by powder X-ray diffraction analysis. Magnetic susceptibility and EPR measurements indicated a paramagnetic high-spin iron centre. Mössbauer spectra revealed the presence of magnetic hyperfine interactions that are temperature-independent down to 4.2?K. The interionic Fe3+ distance of 7.31?Å suggests spin-spin relaxation as the origin of these interactions. 相似文献
6.
The effect of the addition of a second metals such as Zn and Ni on the calcinaton and reduction of alumina, magnesia and silicasupported iron catalysis with total iron loading of 5wt% is investigated by Mössbauer spectroscopy. It is shown that the reducibility of supported α-Fe2O3 is gradually increased by adding the second metal. The values of the magnetic hyperfine field obtained from Mössbauer spectra for the Zn or Ni-added α-Fe2O3 or Fe catalysts decreased with increasing second metal loading. 相似文献
7.
Investigations of the possible use of Mössbauer measurements for the analysis of the corrosion products of iron are reported. The Mössbauer spectrum was measured at room and liquid nitrogen temperatures on two samples produced by different corrosion procedures. The isomeric shift, quadrupole splitting and magnetic splitting observed in the spectra yield information on the chemical composition. In this way, the chemical forms of the compounds in the samples could be established. The magnetic properties, revealed by the spectra taken at different temperatures, permitted the identification of the polymorphous modifications. The rust produced in air saturated with water vapour was found to consist of 50% (w/w) Fe2O3,~40% γ-FeOOH, and ~10% β-FeOOH, while the rust produced by periodical immersion in saturated calcium chloride solution is composed of about equal amounts of β-FeOOH and γ-FeOOH. These findings have been confirmed by the thermoanalytical curves of the samples. The Mössbauer effect presents a convenient method for the investigation of the corrosion products of iron. 相似文献
8.
57Fe Mössbauer spectra of 30CaO·15Al2O3·5Fe2O3·25PbO·25P2O5 glass consist of two quadrupole doublets due to distorted Fe(III)O6 and Fe(II)O6 octahedra. Mössbauer spectra of the aluminophosphate glass irradiated with60Co γ-rays (≈5·104Gy) were essentially the same as those of non-irradiated glass. Mössbauer spectra of γ-ray irradiated aluminophosphate glass, containing 10 stable isotopes (Sr, Y, Zr, Nb, Mo, Ba, La, Ce, Pr, and Nd) as the simulated nuclear waste, were also the same as those of non-irradiated glass. These results indicate that the aluminophosphate glass containing iron and lead has high radiation-durability, in addition to high heat resistivity and high water resistivity. 相似文献
9.
A. Samide I. Bibicu M. S. Rogalski M. Preda 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):593-596
The effect of the NO3? anion on the corrosion of carbon steel in a solution of 0.1M NH4Cl (pH 5.5) was studied by galvanostatic polarization and Mössbauer spectrometry. The anion has an inhibiting effect by decreasing the expansion rate of generalized corrosion of carbon steel in a solution of 0.1M NH4Cl. Mössbauer spectroscopy shows that a superficial compound is formed on the electrode surface as a result of corrosion, presenting no magnetic ordering. Its parameters show the initial stage of corrosion. We assume that at this stage the main corrosion product is a mixture of ferrihydrite Fe(III) and FeOOH (α and/or γ). 相似文献
10.
Christopher M. Burba Roger Frech Agneta Seidel Lennart Häggström Anton Nytén John O. Thomas 《Journal of Solid State Electrochemistry》2009,13(8):1267-1272
The first discharge of the Li+ ion anode material LiSn2(PO4)3 was investigated with Mössbauer spectroscopy and electrochemical techniques. Mössbauer spectroscopy provided insight into the structure of the tin atoms of the fully discharged anode materials. Spectra consist of overlapping peaks, which are assigned to noncrystalline β-Sn and Li–Sn alloy domains. An analysis of the relative intensities of the Mössbauer spectra shows the relative abundance of β-Sn increases at the expense of the Li–Sn alloy as the discharge rate increases. Cell polarization occurs at higher discharge rates, leading to inefficient electrode utilization and poor cycling performance. Sluggish Li+ ion diffusion through the amorphous Li3PO4 network that is formed early in the discharge process might be responsible for the poor electrochemical performance and the accumulation of unalloyed tin. 相似文献
11.
Mössbauer Studies on Sn2O3 Mössbauer data for 119Sn in Sn2O3 show this compound to contain bivalent and tetravalent tin. Whereas tin(IV) is coordinated in a similar way in Sn2O3 and SnO2, a rather large quadrupole splitting indicates an environment of low symmetry for tin(II). 相似文献
12.
V. Ksenofontov S. Reiman M. Waldeck R. Niewa R. Kniep P. Gütlich 《无机化学与普通化学杂志》2003,629(10):1787-1794
The stoichiometric iron nitrides γ′‐Fe4N, ε‐Fe3N and ζ‐Fe2N were characterized by Mössbauer spectroscopy. The thermal decomposition of ε‐Fe3N was studied in‐situ by means of a specially developed Mössbauer furnace. We found ε‐Fe3N to γ′‐Fe4N and ε‐Fe3Nx (x ≥ 1.3) as decomposition products and determined the border of γ′/ε transformation at T ? 930 K. Mössbauer spectroscopy was applied to study in‐situ the thermal decomposition of the nitridometalate Li3[FeIIIN2] and the formation of Li2[(Li1‐xFeIx)N], the compound with the largest local magnetic field ever observed in an iron containing material. The kinetics of formation and the stability of Li2[(Li1‐xFeIx)N] was of particular interest in the present study. 相似文献
13.
T. A. Lastovina A. L. Bugaev S. P. Kubrin E. A. Kudryavtsev A. V. Soldatov 《Journal of Structural Chemistry》2016,57(7):1444-1449
Magnetic nanoparticles and those doped with rare-earth metal ions having spinel structure were synthesized, possessing the average particles size of 11.3-13.4 nm. According to Mössbauer spectroscopy data it can be concluded that prepared iron oxide nanoparticles are γ-Fe2O3. For materials containing rare-earth elements the decrease of octahedral component surface was observed in comparison to non-doped material, what can be explained by Eu3+, Sm3+ и Gd3+ ions occupying the octahedral position. 相似文献
14.
MnxZn1−xFe2O4 (x = 0.05…0.9) nanoparticles prepared via sol–gel hydrothermal process were investigated by X-ray powder diffractometry (XRPD), transmission electron microscopy (TEM), 57Fe Mössbauer spectroscopy (MS), electron paramagnetic resonance spectroscopy (EPR), X-ray absorption near edge structure spectroscopy (XANES) and magnetic hysteresis measurements. XRPD measurements revealed a non-monotonic dependence of the cubic lattice parameter on the Mn concentration, which is interpreted as being the result of a corresponding variation in the inversion degree (concentration of Fe ions on the occupied tetrahedral lattice sites) of the studied spinels. XANES measurements indicated that the average oxidation state of Mn ions decreases with the applied Mn concentration, in contrast with Fe ions that were found to be exclusively in the 3+ oxidation state by MS measurements. EPR spectra recorded as a function of temperature enabled the determination of the characteristic anisotropy energy barrier of the superparamagnetic particles, and contributed to the clarification of peculiarities of the corresponding 57Fe Mössbauer spectra. On the basis of the observed results the interdependences among the sample stoichiometry, the cubic cell parameter, the particle size, the inversion degree, the magnetic ordering temperature and the effective magnetic anisotropy are discussed. 相似文献
15.
Jürgen Pebler Klaus Schmidt Kurt Dehnicke Prof. Dr. Johann Weidlein 《无机化学与普通化学杂志》1978,440(1):269-277
121Sb Mössbauer Spectra of Antimony (V) Compounds. II The Mössbauer resonance effect of 121Sb has been studied at 4.2 K in a series of 11 antimony(V) compounds which are in most cases bridged. Isomer shift and quadrupole splitting variations are considered in the light of results of X-ray and vibrational spectroscopy. Preparation and the vibrational spectra of [NMe4][SbCl4(n3)2] are described. Within the limitations of available structural data related tin compounds are compared with those of corresponding 119Sn Mössbauer spectra. 相似文献
16.
J. C. Grenier L. Fournes M. Pouchard P. Hagenmuller M. Parras M. Vallet J. Calbet 《无机化学与普通化学杂志》1989,576(1):108-116
The BaFeO3?y phase, the structure of which is related to the 6H-type hexagonal perovskite, has been investigated for y = 0.28 using in particular Mössbauer spectroscopy. An X-ray diffraction analysis of BaFeO2.72 reveals a quite similar pattern to that of the stoichiometric 6H-BaTiO3, but Mössbauer resonance data show the oxygen vacancies to result likely in the formation of distorted pyramidal sites containing high spin iron (IV). 相似文献
17.
D. S. Kulgawczuk K. Ruebenbauer B. Sepiol 《Journal of Radioanalytical and Nuclear Chemistry》1989,131(1):43-50
Ferrous gluconate Fe(C6H11O7)2·2H2O was investigated by means of57Fe (14.4 keV)-Mössbauer spectroscopy and thermogravimetry. The Mössbauer study was performed in the temperature range 80 to 423 K. It was found that Fe2+ occupies two distinctly different Mössbauer sites in the hydrated phase and a single site in the product of the thermal treatment. All samples were contaminated by some amount of Fe3+. A significant oxidation occurs during thermal treatment (about 378 K) at least for the samples exposed to the air. No Goldanskii-Karyagin effect has been detected, in contrast to the previous claim. It has to be noted that the ferrous gluconate is often used as the iron containing component of drugs used in the treatment of anaemia. 相似文献
18.
A series of nanostructured iron compounds including cubic Fe3O4 and orthorhombic FeOOH were synthesized via a facile low temperature (in the range of 60?100°C) solution method. In the whole process, the interaction between FeCl2·4H2O and methenamine (C6H12N4) was carried out through a reflux device under different reaction conditions such as temperature, solvent, and duration. The samples were detected by XRD, TEM, SAED, physical property measurement system, and Mössbauer spectroscopy, separately. The experiments showed that magnetic mixture nanoparticles had flake and rod morphologies, and cubic Fe3O4 took on grain nanostructure. Magnetism measurements indicated that the saturated magnetization of the as-obtained magnetic mixture was lower than that of the cubic magnetite. Mössbauer spectroscopy testified the sample consisting of cubic magnetite rather than γ-Fe2O3. In addition, a possible growth mechanism of cubic magnetic nanoparticles under different conditions was discussed. 相似文献
19.
Concentrations of up to 20 mol.% Dy have been substituted for tetravalent cerium in the perovskite BaCeO3. 161Dy Mössbauer spectroscopy demonstrates that the dysprosium in this host is present in the trivalent oxidation state. Effective magnetic moments obtained on the same samples confirm these findings. Line broadening as a function of dysprosium concentration, observed from both X-ray and Mössbauer measurements, is attributed to the presence of lattice defects (oxygen vacancies) which are necessary for charge compensation. 相似文献
20.
The products obtained from molten and aqueous SnF2:MI systems (M = Na, K, Rb, and NH4) have been studied. The Mössbauer data for phases with 1:1, 2:1, and 3:1 SnF2:MI molar ratios are reported. The MSnIF2 phases show evidence of two tin sites, one of which has Mössbauer parameters attributable to an octahedral tin(II) environment. The materials obtained are all colored and the reasons for these colors are discussed. 相似文献