scholarly journals Oxidation State and Local Structure of Chromium Ions in LaOCl

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3539
Author(s):  
Andris Antuzevics ◽  
Guna Krieke ◽  
Haralds Ozols ◽  
Andris Fedotovs ◽  
Anatolijs Sarakovskis ◽  
...  
Keyword(s):  
Oxidation State ◽  
Local Structure ◽  
Double Resonance ◽  
Lattice Parameter ◽  
Subsequent Treatment ◽  
Simultaneous Increase ◽  
Electron Nuclear Double Resonance ◽  
X Ray ◽  
Chromium Ions ◽  
State And Local

LaOCl doped with 0–10 mol% Cr was synthesized by thermal decomposition of chlorides. X-ray diffraction (XRD) analysis revealed that incorporation of chromium results in a decrease of the lattice parameter a and a simultaneous increase of the lattice parameter c. The local structure of chromium ions was studied with X-ray photoelectron (XPS), X-ray absorption (XANES), multifrequency electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopy techniques. It was determined that synthesis in oxidizing atmosphere promotes the incorporation of chromium ions predominantly in the 5+ oxidation state. Changes of chromium oxidation state and local environment occur after a subsequent treatment in reducing atmosphere. Spin-Hamiltonian (SH) parameters for a Cr5+ and two types of Cr3+ centers in LaOCl were determined from the EPR spectra simulations.

scholarly journals Local Structure and Magnetism of LiFeSi0.01P0.99O4/C as a Cathode Material on Lithium-Ion Battery

2021 ◽  
Vol 1 (1) ◽  
pp. 1-4
Author(s):  
Vera Laviara Maghfirohtuzzoimah ◽  
Sahara Hamas Intifadhah ◽  
Pelangi Az-zahra ◽  
Wantana Klysubun ◽  
Dita Puspita Sari ◽  
...  
Keyword(s):  
Lithium Ion Battery ◽  
Oxidation State ◽  
Local Structure ◽  
Lithium Ion ◽  
Antiferromagnetic Order ◽  
Main Peak ◽  
X Ray ◽  
State And Local ◽  
Silicon Doped ◽  
X Ray Absorption

The oxidation state and local structure of LiFeSi0.01P0.99O4/C composites as a cathode on lithium-ion battery were investigated by Fe K-edge X-ray Absorption Near Edge Spectroscopy (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). The LiFeSi0.01P0.99O4/C sample was prepared by solid-state reaction process. Based on the XANES analysis, the absorption of edge energy (E0) of the sample was 7124.92 eV. In addition, linear combination fitting (LCF) analysis of XANES confirmed the oxidation state of iron mixture of 2+ and 3+ as the effect of silicon doped in LiFePO4. The Fourier Transform (FT) of the Fe K-edge EXAFS fitting analysis showed that the nearest neighbors surrounding atom Fe were the main peak with high intensity that confirmed Fe-O bond; the second and third peak with lower intensity confirmed Fe-P and Fe-Fe bonds, respectively. In addition, the SQUID magnetometer result of LiFeSi0.01P0.99O4/C indicated the antiferromagnetic order temperature of LiFeSi0.01P0.99O4/C at ~51 K with the indication of the presence of impurity and structural distortion.

Europium oxidation state and local structure in silicate glasses

2012 ◽  
Vol 97 (5-6) ◽  
pp. 918-929 ◽  
Author(s):  
M. R. Cicconi ◽  
G. Giuli ◽  
E. Paris ◽  
W. Ertel-Ingrisch ◽  
P. Ulmer ◽  
...  
Keyword(s):  
Oxidation State ◽  
Local Structure ◽  
Silicate Glasses ◽  
State And Local

Chemical State and Local Structure around Titanium Atoms in NaAlH4Doped with TiCl3Using X-ray Absorption Spectroscopy

2004 ◽  
Vol 108 (42) ◽  
pp. 16372-16376 ◽  
Author(s):  
Aline Léon ◽  
Oliver Kircher ◽  
Jörg Rothe ◽  
Maximilian Fichtner
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chemical State ◽  
X Ray ◽  
State And Local ◽  
X Ray Absorption

Iron oxidation state and local structure in North American tektites

2010 ◽  
Author(s):  
Gabriele Giuli ◽  
Sigrid Griet Eeckhout ◽  
Maria Rita Cicconi ◽  
Christian Koeberl ◽  
Giovanni Pratesi ◽  
...  
Keyword(s):  
Oxidation State ◽  
North American ◽  
Local Structure ◽  
Iron Oxidation ◽  
Iron Oxidation State ◽  
State And Local

scholarly journals Manganese co-localizes with calcium and phosphorus in Chlamydomonas acidocalcisomes and is mobilized in manganese-deficient conditions

2019 ◽  
Vol 294 (46) ◽  
pp. 17626-17641 ◽  
Author(s):  
Munkhtsetseg Tsednee ◽  
Madeli Castruita ◽  
Patrice A. Salomé ◽  
Ajay Sharma ◽  
Brianne E. Lewis ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Storage Capacity ◽  
Double Resonance ◽  
Algal Growth ◽  
Drastic Reduction ◽  
Electron Nuclear Double Resonance ◽  
X Ray ◽  
Mutant Strains ◽  
X Ray Absorption ◽  
Secondary Ion

Exposing cells to excess metal concentrations well beyond the cellular quota is a powerful tool for understanding the molecular mechanisms of metal homeostasis. Such improved understanding may enable bioengineering of organisms with improved nutrition and bioremediation capacity. We report here that Chlamydomonas reinhardtii can accumulate manganese (Mn) in proportion to extracellular supply, up to 30-fold greater than its typical quota and with remarkable tolerance. As visualized by X-ray fluorescence microscopy and nanoscale secondary ion MS (nanoSIMS), Mn largely co-localizes with phosphorus (P) and calcium (Ca), consistent with the Mn-accumulating site being an acidic vacuole, known as the acidocalcisome. Vacuolar Mn stores are accessible reserves that can be mobilized in Mn-deficient conditions to support algal growth. We noted that Mn accumulation depends on cellular polyphosphate (polyP) content, indicated by 1) a consistent failure of C. reinhardtii vtc1 mutant strains, which are deficient in polyphosphate synthesis, to accumulate Mn and 2) a drastic reduction of the Mn storage capacity in P-deficient cells. Rather surprisingly, X-ray absorption spectroscopy, EPR, and electron nuclear double resonance revealed that only little Mn2+ is stably complexed with polyP, indicating that polyP is not the final Mn ligand. We propose that polyPs are a critical component of Mn accumulation in Chlamydomonas by driving Mn relocation from the cytosol to acidocalcisomes. Within these structures, polyP may, in turn, escort vacuolar Mn to a number of storage ligands, including phosphate and phytate, and other, yet unidentified, compounds.

scholarly journals Local Structure of Iridate Pyrochlores from Hydrothermal Synthesis

2014 ◽  
Vol 70 (a1) ◽  
pp. C869-C869
Author(s):  
Helen Playford ◽  
Ravi SINGH ◽  
Lieh Jeng Chang ◽  
Kripasindhu Sardar ◽  
Alex Hannon ◽  
...  
Keyword(s):  
Local Structure ◽  
Synthesis Method ◽  
Pyrochlore Structure ◽  
Magnetic Ordering ◽  
Structural Disorder ◽  
Lattice Parameter ◽  
Magnetic Behaviour ◽  
Total Scattering ◽  
X Ray ◽  
Cation Content

Iridate pyrochlores of general formula M2Ir2O7have potential applications in catalysis [1]. They also often exhibit unusual magnetic and electronic properties caused by spin-orbit coupling and geometric frustration [2]. A detailed understanding of structure is necessary to enable these properties to be understood and exploited. Because of the propensity of the pyrochlore structure to accommodate structural disorder, we have chosen to utilise the technique of total scattering to examine the structure of M2Ir2O7(M = Bi, Nd). The sensitivity of our measurements to all the constituent elements is maximised by the combination of both neutron and X-ray total scattering. We find no evidence for magnetic ordering in our samples of Nd2Ir2O7, in contrast to literature reports [3]. By comparing the local structure of our samples with that of one reported to exhibit magnetic ordering, we explore the possibility of a structural origin for the differences in magnetic behaviour. We have found that synthesis method can directly influence the structure of these iridate pyrochlores. Local structural analysis provides evidences of A-site cation deficiency and partial oxidation of Ir(IV) to Ir(V) in samples produced by hydrothermal techniques. Irreversible changes to the lattice parameter upon heating these samples at 400 – 9000C further support the inference that the cation content is somewhat variable. We report the results of reverse Monte Carlo (RMC) refinements using the program RMCProfile, which is capable of simultaneously fitting to X-ray and neutron data, and therefore provides structural models of the greatest possible accuracy. We also report the results of in situ X-ray total scattering measurements which provide local-scale insight into the interesting thermal behaviour and apparent flexible cation content of these materials.

In situ XAS investigation of the oxidation state and local structure of vanadium in discharged and charged V2O5 aerogel cathodes

2002 ◽  
Vol 47 (19) ◽  
pp. 3151-3161 ◽  
Author(s):  
A.N Mansour ◽  
P.H Smith ◽  
W.M Baker ◽  
M Balasubramanian ◽  
J McBreen
Keyword(s):  
Oxidation State ◽  
Local Structure ◽  
In Situ Xas ◽  
State And Local
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