scholarly journals Evidence for the charge disproportionation of iron in extraterrestrial bridgmanite

2020 ◽  
Vol 6 (2) ◽  
pp. eaay7893 ◽  
Author(s):  
Luca Bindi ◽  
Sang-Heon Shim ◽  
Thomas G. Sharp ◽  
Xiande Xie
Keyword(s):  
High Pressure ◽  
Metallic Iron ◽  
Valence State ◽  
Lower Mantle ◽  
Direct Evidence ◽  
Mixed Valence ◽  
Disproportionation Reaction ◽  
Redox Processes ◽  
Charge Disproportionation ◽  
Suizhou Meteorite

Bridgmanite, MgSiO3 with perovskite structure, is considered the most abundant mineral on Earth. On the lower mantle, it contains Fe and Al that strongly influence its behavior. Experimentalists have debated whether iron may exist in a mixed valence state, coexistence of Fe2+ and Fe3+ in bridgmanite, through charge disproportionation. Here, we report the discovery of Fe-rich aluminous bridgmanite coexisting with metallic iron in a shock vein of the Suizhou meteorite. This is the first direct evidence in nature of the Fe disproportionation reaction, which so far has only been observed in some high-pressure experiments. Furthermore, our discovery supports the idea that the disproportionation reaction would have played a key role in redox processes and the evolution of Earth.

Mixed-valence state and structure changes of EuH (x = 2 and 2 < x ≤ 3) under high-pressure H2 atmosphere

2021 ◽  
Vol 865 ◽  
pp. 158637
Author(s):  
Keiji Kuno ◽  
Takahiro Matsuoka ◽  
Ryo Masuda ◽  
Takaya Mitsui ◽  
Makoto Seto ◽  
...  
Keyword(s):  
High Pressure ◽  
Valence State ◽  
Mixed Valence ◽  
Mixed Valence State ◽  
Structure Changes

Theory for the mixed-valence state

1979 ◽  
Vol 40 (C5) ◽  
pp. C5-374-C5-374 ◽  
Author(s):  
C. M. Varma
Keyword(s):  
Valence State ◽  
Mixed Valence ◽  
Mixed Valence State

MIXED VALENCE STATE OF Sm ON THE SURFACE OF AMORPHOUS La80-xSmxAu20 ALLOYS

1980 ◽  
Vol 41 (C8) ◽  
pp. C8-799-C8-802 ◽  
Author(s):  
G. Krill ◽  
A. Amamou ◽  
A. Berrada ◽  
J. Durand ◽  
N. Hassanain
Keyword(s):  
Valence State ◽  
Mixed Valence ◽  
Mixed Valence State

scholarly journals From Slater to Mott physics by epitaxially engineering electronic correlations in oxide interfaces

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Carla Lupo ◽  
Evan Sheridan ◽  
Edoardo Fertitta ◽  
David Dubbink ◽  
Chris J. Pickard ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Charge Transfer ◽  
Lower Mantle ◽  
Random Structure ◽  
Titanium Oxides ◽  
Oxide Interfaces ◽  
Electronic Correlations ◽  
Epitaxial Strain ◽  
Magnetic Switching

AbstractUsing spin-assisted ab initio random structure searches, we explore an exhaustive quantum phase diagram of archetypal interfaced Mott insulators, i.e. lanthanum-iron and lanthanum-titanium oxides. In particular, we report that the charge transfer induced by the interfacial electronic reconstruction stabilises a high-spin ferrous Fe2+ state. We provide a pathway to control the strength of correlation in this electronic state by tuning the epitaxial strain, yielding a manifold of quantum electronic phases, i.e. Mott-Hubbard, charge transfer and Slater insulating states. Furthermore, we report that the electronic correlations are closely related to the structural oxygen octahedral rotations, whose control is able to stabilise the low-spin state of Fe2+ at low pressure previously observed only under the extreme high pressure conditions in the Earth’s lower mantle. Thus, we provide avenues for magnetic switching via THz radiations which have crucial implications for next generation of spintronics technologies.

A one-dimensional chloride-bridged PtII/PtIVmixed-valence complex with a 4-[(4-hydroxyphenyl)diazenyl]benzenesulfonate counter-ion

2015 ◽  
Vol 71 (12) ◽  
pp. 1033-1036 ◽  
Author(s):  
Nobuyuki Matsushita ◽  
Ayako Taira
Keyword(s):  
Valence State ◽  
Title Compound ◽  
Linear Chain ◽  
Mixed Valence ◽  
Chain Structure ◽  
Structural Parameter ◽  
One Dimensional ◽  
Square Planar ◽  
Cl Atoms ◽  
Linear Chain Structure

The title compound,catena-poly[[[bis(ethylenediamine-κ2N,N′)platinum(II)]- μ-chlorido-[bis(ethylenediamine)platinum(IV)]-μ-chlorido] tetrakis{4-[(4-hydroxyphenyl)diazenyl]benzenesulfonate} dihydrate], {[PtIIPtIVCl2(C2H8N2)4](HOC6H4N=NC6H4SO3)4·2H2O}n, has a linear chain structure composed of square-planar [Pt(en)2]2+(en is ethylenediamine) and elongated octahedraltrans-[PtCl2(en)2]2+cations stacked alternately, bridged by Cl atoms, along thebaxis. The Pt atoms are located on an inversion centre, while the Cl atoms are disordered over two sites and form a zigzag ...Cl—PtIV—Cl...PtII... chain, with a PtIV—Cl bond length of 2.3140 (14) Å, an interatomic PtII...Cl distance of 3.5969 (15) Å and a PtIV—Cl...PtIIangle of 170.66 (6)°. The structural parameter indicating the mixed-valence state of the Pt atom, expressed by δ = (PtIV—Cl)/(PtII...Cl), is 0.643.

scholarly journals Mixed-Valence State of Europium in the Misfit Layer Compound (EuS)1.173NbS2.

ChemInform ◽  
2003 ◽  
Vol 34 (20) ◽  
Author(s):  
Laurent Cario ◽  
Pierre Palvadeau ◽  
Alain Lafond ◽  
Catherine Deudon ◽  
Yves Moelo ◽  
...  
Keyword(s):  
Valence State ◽  
Mixed Valence ◽  
Layer Compound ◽  
Mixed Valence State

scholarly journals Investigation of Mixed Valence State of Sm_{1-x}B_{6} and Sm_{1-x}La_{x}B_{6} by XANES

2014 ◽  
Vol 126 (1) ◽  
pp. 338-339 ◽  
Author(s):  
S. Gabáni ◽  
K. Flachbart ◽  
J. Bednarčík ◽  
E. Welter ◽  
V. Filipov ◽  
...  
Keyword(s):  
Valence State ◽  
Mixed Valence ◽  
Mixed Valence State
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