Tuning of the Physical Properties in Mixed Valence Inorganic Solids by Oriented Cationic and Anionic Substitutions

2012 ◽  
Vol 638 (10) ◽  
pp. 1640-1640
Author(s):  
Kledi Xhaxhiu ◽  
Hans-Jörg Deiseroth ◽  
Rüdiger Schmidt-Grund ◽  
Klaus Bente
Keyword(s):  
Physical Properties ◽  
Mixed Valence ◽  
Inorganic Solids

Mixed-valence Fe(III)Fe(IV) dimers. Preparation and physical properties of oxidation products of oxo-bridged binuclear iron(III) complexes

1995 ◽  
Vol 238 (1-2) ◽  
pp. 139-147 ◽  
Author(s):  
V.K. Voronkova ◽  
J. Mrozinski ◽  
M.A. Yampol'skaya ◽  
Yu.V. Yablokov ◽  
N.S. Evtushenko ◽  
...  
Keyword(s):  
Physical Properties ◽  
Mixed Valence ◽  
Oxidation Products ◽  
Binuclear Iron

scholarly journals Effect of Transition Metal Substitution on the Charge-Transfer Phase Transition and Ferromagnetism of Dithiooxalato-Bridged Hetero Metal Complexes, (n-C3H7)4N[FeII1−xMnIIxFeIII(dto)3]

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 446 ◽  
Author(s):  
Masaya Enomoto ◽  
Hiromichi Ida ◽  
Atsushi Okazawa ◽  
Norimichi Kojima
Keyword(s):  
Phase Transition ◽  
Charge Transfer ◽  
Physical Properties ◽  
Mixed Valence ◽  
Ferromagnetic Phase ◽  
Ferromagnetic Transition ◽  
Transfer Phase ◽  
Spin Configuration ◽  
Ion Radius ◽  
The Difference

The dithiooxalato-bridged iron mixed-valence complex (n-C3H7)4N[FeIIFeIII(dto)3] (dto = dithiooxalato) undergoes a novel charge-transfer phase transition (CTPT) accompanied by electron transfer between adjacent FeII and FeIII sites. The CTPT influences the ferromagnetic transition temperature according to the change of spin configuration on the iron sites. To reveal the mechanism of the CTPT, we have synthesized the series of metal-substituted complexes (n-C3H7)4N[FeII1-xMnIIxFeIII(dto)3] (x = 0–1) and investigated their physical properties by means of magnetic susceptibility and dielectric constant measurements. With increasing MnII concentration, x, MnII-substituted complexes show the disappearance of CTPT above x = 0.04, while the ferromagnetic phase remains in the whole range of x. These results are quite different from the physical properties of the ZnII-substituted complex, (n-C3H7)4N[FeII1-xZnIIxFeIII(dto)3], which is attributed to the difference of ion radius as well as the spin states of MnII and ZnII.

Mixed Valence Oxide ((Sb,As)2O) Mo45+Mo66+O30: Synthesis, Crystal Structure and Physical Properties.

ChemInform ◽  
2004 ◽  
Vol 35 (43) ◽  
Author(s):  
Juan E. Iglesias ◽  
Alicia Castro ◽  
Renee Enjalbert ◽  
Jean Galy
Keyword(s):  
Crystal Structure ◽  
Physical Properties ◽  
Mixed Valence

Fine-Tuning the Physical Properties of Perovskite Related La-Ti-Oxides by Merely Altering the Oxygen Stoichiometry

2000 ◽  
Vol 658 ◽  
Author(s):  
Olav Becker ◽  
Stefan Ebbinghaus ◽  
Bernd Renner ◽  
Armin Reller
Keyword(s):  
Physical Properties ◽  
Structural Changes ◽  
Mixed Valence ◽  
Fine Tuning ◽  
Oxygen Stoichiometry ◽  
Electron Microscopic ◽  
Structural Mechanism ◽  
Oxidation Processes ◽  
Structural Framework ◽  
Intermediate Phases

ABSTRACTThe isostructural oxides LaTiO3.5, SrNbO3.5 and CaNbO3.5 adopt layered structures made up of perovskite related slabs intermitted by layers of non-linking BO6-octahedra (B=Ti, Nb). In these phases the transition metals Ti and Nb are in their highest oxidation states +IV and +V, respectively. They are insulators, in the case of the Ti phase a ferroelectric insulator with the highest known Tc (above 1700°C). By changing the oxygen stoichiometry, i.e. by controlled reduction or re-oxidation processes in the range of 2ABO3.5 ø 2ABO3 + ½ O2 (A=La or Sr, B=Ti or Nb) mixed valence phases are obtained. Accordingly, the physical properties of the different phases alter from insulating to semiconducting or to conducting. Detailed studies on the structural changes reveal, however, that the sublattice of the metal cations is basically conserved. In principle the reduction corresponds to a condensation of the perovskite layers leading to intermediate phases such as the semiconducting LaTiO3.4, in which five TiO6-octahedra thick perovskite slabs constitute the structural framework and 20% of the Ti+IV cations are reduced to Ti+III. Conductivity measurements using single crystals of the corresponding Ti and Nb phases reveal that these mixed valence oxides must be considered as one-dimensional conductors. The fully reduced phases La+IIITi+IIIO3 and Sr+IINb+IVO3 adopt distorted perovskite structures. Extensive high resolution electron microscopic and light microscopic investigations have been carried out in order to characterize the structural mechanism of the reversible, highly topotactic reduction and re-oxidation processes. Thermogravimetric measurements in reducing and oxidizing atmospheres have been performed for the identification of the temperature ranges wherein the decisive mass changes take place. The results of the described experiments support that the properties of such metal oxides can be finely and reversibly tuned by merely changing the oxygen stoichiometries.

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