scholarly journals Spectral studies of bismuth-containing pyrochlores

2021 ◽  
Vol 2103 (1) ◽  
pp. 012146
Author(s):  
S V Nekipelov ◽  
N A Zhuk ◽  
O V Petrova ◽  
D V Sivkov ◽  
K A Bakina ◽  
...  
Keyword(s):  
Charge State ◽  
Solid Solutions ◽  
Pyrochlore Structure ◽  
Spectral Studies ◽  
Nexafs Spectroscopy ◽  
Cobalt Nickel ◽  
Metal Atoms ◽  
Thermal Stable

Abstract Thermal stable solid solutions of titanates, niobates, and tantalates of bismuth with a pyrochlore structure doped with 3d-metal atoms were studied using XPS and NEXAFS spectroscopy. Based on spectral studies, it was shown that the manganese, cobalt, nickel and copper atoms in these solid solutions have mainly charge state +2 and iron atoms – charge state +3.

scholarly journals NEXAFS–Spectra and Magnetic Susceptibility of Nickel and Chromium Doped of Bismuth Niobate

2020 ◽  
pp. 340-348
Author(s):  
Irina E. Vasilyeva ◽  
Sergey V. Nekipelov ◽  
Boris A. Makeev ◽  
Alexey G. Krasnov ◽  
Nadezhda A. Zhuk
Keyword(s):  
Magnetic Susceptibility ◽  
Charge State ◽  
Electronic State ◽  
High Spin ◽  
Solid Solutions ◽  
Exchange Interactions ◽  
High Spin State ◽  
Chromium Oxides ◽  
X Ray ◽  
Nexafs Spectroscopy

The electronic state and character of exchange interactions of nickel and chromium atoms in solid solutions of Bi5Nb3-3xМ3xO15-δ (М-Cr,Ni) was researched by methods of magnetic susceptibility and NEXAFS-spectroscopy. NEXAFS spectra of nickel and chromium oxides were obtained. According to X-ray spectroscopy in solid solutions, chromium atoms are mainly in the charge state of Cr(III), and nickel atoms in the high-spin state of Ni(II) in octahedral coordination. In solid solutions, paramagnetic chromium and nickel atoms are present in the form of monomers and clusters with a common antiferromagnetic type of exchange

scholarly journals Magnetic behavior of Fe-doped of multicomponent bismuth niobate pyrochlore

2021 ◽  
Vol 60 (1) ◽  
pp. 38-46
Author(s):  
Nadezhda A. Zhuk ◽  
Boris A. Makeev ◽  
Sergey V. Nekipelov ◽  
Maria V. Yermolina ◽  
Anna V. Fedorova ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Solid Phase ◽  
Synthesis Method ◽  
Pyrochlore Structure ◽  
Exchange Interactions ◽  
Magnetic Behavior ◽  
Susceptibility Data ◽  
Nexafs Spectroscopy ◽  
Magnetic Dilution ◽  
Paramagnetic Atoms

Abstract Two series of iron-containing solid solutions Bi2Mg1− x Fe x Nb2O9+δ and Bi2MgNb2−2 x Fe2 x O9−δ of pyrochlore structure were obtained by the traditional solid phase synthesis method. The electronic state and character of exchange interactions of iron atoms in solid solutions were investigated by methods of magnetic dilution and NEXAFS-spectroscopy. According to X-ray spectroscopy and magnetic susceptibility data, iron(III) atoms are distributed mainly in octahedral positions of niobium(V) and in a dominant amount are in the charge state of Fe(III) in the form of monomers and exchange-bonded clusters mainly with antiferromagnetic type of exchange. Differences in magnetic behavior of iron-containing solid solutions of both series have been revealed. Antiferromagnetic and ferromagnetic exchange can be realized between iron atoms, which, with increasing concentration of paramagnetic atoms and averaging structure distortions, becomes less significant. The parameters of exchange interactions in clusters and distribution of iron paramagnetic atoms depending on the concentration of solid solutions have been calculated.

Novel 1-D Chains Constructed of Rings Which Include Six Metal Atoms [M2Au4] (M = Ni, Zn) with Aurophilic Interactions: Structure, Magnetic, and Spectral Studies

2005 ◽  
Vol 88 (11) ◽  
pp. 3000-3010 ◽  
Author(s):  
Shu-Ping Wang ◽  
You Song ◽  
Dong-Zhao Gao ◽  
Li-Cun Li ◽  
Qing-Mei Wang ◽  
...  
Keyword(s):  
Spectral Studies ◽  
Metal Atoms ◽  
Aurophilic Interactions

Complexes of propyl mercury thiocyanates with cobalt, nickel, and zinc thiocyanate

1982 ◽  
Vol 60 (18) ◽  
pp. 2351-2354 ◽  
Author(s):  
P. P. Singh ◽  
V. P. Singh
Keyword(s):  
General Formula ◽  
Spectral Studies ◽  
Lewis Bases ◽  
Cobalt Nickel ◽  
Anionic Complexes

RHgSCN (R = n-C3H7, (iso-C3H7) react with M(NCS)2 (M = Co(II), Ni(II), Zn(II)) to form compounds of general formula (SCN)2M(NCSHgR)2. Conductance measurements and infrared and electronic spectral studies indicate that M and mercury atoms are linked by bridging thiocyanate groups. Cobalt and zinc are tetrahedrally coordinated, whereas nickel is octahedral. With the exception of zinc analogs, these compounds form complexes with Lewis bases. Pyridine and nicotinamide form adducts of general formula L2(SCN)2M(NCSHgR)2, while 2,2′-bipyridine and 1,10-phenanthroline form cationic–anionic complexes of formula [M(L—L)3][RHg(SCN)2]2.

Five-coordination in complexes of 2-(3,5-Dimethylpyrazol-1-yl)quinoline, a sterically hindered diimine system

1984 ◽  
Vol 37 (12) ◽  
pp. 2421 ◽  
Author(s):  
AT Baker ◽  
NJ Ferguson ◽  
HA Goodwin
Keyword(s):  
Water Molecule ◽  
Cobalt Complex ◽  
X Ray Diffraction ◽  
Iron Cobalt ◽  
Coordination Environment ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cobalt Nickel ◽  
Metal Atoms ◽  
Sterically Hindered Diimine

The bidentate diimine-type ligand 2-(3,5-dimethylpyrazol-1-yl)quinoline forms mono complexes with the bivalent chlorides of iron, cobalt, nickel and copper. These complexes are magnetically dilute, but electronic spectral data indicate that, except for the cobalt complex which is tetrahedral, the metal atoms are five-coordinate and hence a chloro-bridged structure is proposed. The cobalt(II) complex readily adds a water molecule, and structure determination by X-ray diffraction shows that the complex aquadichloro[2-(3,5-dimethylpyrazol-1-yl)quinoline]cobalt(II) is monomeric and five-coordinate, the coordination environment approximating trigonal bipyramidal.

scholarly journals Phase Transformations, Magnetic Susceptibility and NEXAFS-Spectra of Cobalt-Doped Solid Solutions of Bismuth Orthoniobate

2020 ◽  
pp. 89-98
Author(s):  
Nadezhda A. Zhuk ◽  
Lubov V. Rychkova ◽  
Sergey V. Nekipelov ◽  
Boris A. Makeev
Keyword(s):  
Magnetic Susceptibility ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Electronic State ◽  
Solid Solutions ◽  
Electron State ◽  
Exchange Interactions ◽  
X Ray ◽  
Nexafs Spectroscopy ◽  
Charge States

The electron state and the nature of the exchange interactions of cobalt atoms in BiNb1-xСoxO4-δ solid solutions of triclinic and orthorhombic modifications were studied using the magnetic susceptibility and NEXAFS-spectroscopy. In order to determine the electronic state of cobalt atoms, the solid solutions and oxides of cobalt CoO, Co3O4 were studied by NEXAFS-spectroscopy. The X-ray spectroscopy and the study of the magnetic susceptibility of the solid solutions revealed the presence of the monomers and exchange-related clusters of cobalt with the Co(II) and Co(III) charge states characterized mostly by the antiferromagnetic type of exchange. The cobalt containing solid solutions allowed us to confirm the reversibility of the α↔β-BiNbO4 phase transformation

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