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Full-Text Articles in Physical Sciences and Mathematics

Bis(Tetra­Phenyl­Arsonium) Hexa­Fluorido­Technetate(Iv) Dihydrate: Preparation, Structure And Spectroscopic Analysis, Samundeeswari Mariappan Balasekaran, Frederic Poineau Nov 2019

Bis(Tetra­Phenyl­Arsonium) Hexa­Fluorido­Technetate(Iv) Dihydrate: Preparation, Structure And Spectroscopic Analysis, Samundeeswari Mariappan Balasekaran, Frederic Poineau

Chemistry and Biochemistry Faculty Research

Reports of quadrivalent transition-metal fluoride salts containing bulky organic cations are limited. In this context, we prepared the bis­(tetra­phenyl­arsonium) hexa­fluorido­technetate(IV) dihydrate salt, (C24H20As)2[TcF6]·2H2O, by a cation metathesis reaction of (NH4)2[TcF6] in water. This is the first report of an arsonium salt of the hexa­fluorido­technetate(IV) dianion. (AsPh4)2[TcF6]·2H2O crystallizes in the triclinic space group P[\overline{1}]. The [TcF6]2− anion adopts a slightly distorted octa­hedral geometry with an average Tc—F bond length of 1.933 Å. The cyclic voltammogram of (AsPh4)2[TcF6]·2H2O in CH3CN shows a one-electron reversible oxidation wave at 1.496 V.


An Unexpected Rhenium(Iv)–Rhenium(Vii) Salt: [Co(Nh3)6]3[Reviio4][Reivf6]46h2o, James Louis_Jean, Samudee Mariappan Balasekaran, Adelheid Hagenbach, Frederic Poineau Jul 2019

An Unexpected Rhenium(Iv)–Rhenium(Vii) Salt: [Co(Nh3)6]3[Reviio4][Reivf6]46h2o, James Louis_Jean, Samudee Mariappan Balasekaran, Adelheid Hagenbach, Frederic Poineau

Chemistry and Biochemistry Faculty Research

The title hydrated salt, tris[hexaamminecobalt(III)] tetraoxidorhenate(VII) tetrakis[hexafluoridorhenate(IV)] hexahydrate, arose unexpectedly due to possible contamination of the K2ReF6 starting material with KReO4. It consists of octahedral [Co(NH3)6] 3+ cation (Co1 site symmetry 1), tetrahedral [ReVIIO4] anions (Re site symmetry 1) and octahedral [ReIVF6] 2 anions (Re site symmetries 1and 3). The [ReF6] 2 octahedral anions (mean Re—F = 1.834 A˚ ), [Co(NH3)6] 3+ octahedral cations (mean Co—N = 1.962 A˚ ), and the [ReO4] tetrahedral anion (mean Re—O = 1.719 A˚ ) are slightly distorted. A network of N—HF hydrogen bonds consolidates the structure. The crystal studied was refined as a …


Magnetic Borophenes From An Evolutionary Search, Meng-Hong Zhu, Xiao-Ji Weng, Guoying Gao, Shuai Dong, Ling-Fang Lin, Wei-Hua Wang, Qiang Zhu, Artem R. Oganov, Xiao Dong, Yongjun Tian, Xiang-Feng Zhou, Hui-Tian Wang May 2019

Magnetic Borophenes From An Evolutionary Search, Meng-Hong Zhu, Xiao-Ji Weng, Guoying Gao, Shuai Dong, Ling-Fang Lin, Wei-Hua Wang, Qiang Zhu, Artem R. Oganov, Xiao Dong, Yongjun Tian, Xiang-Feng Zhou, Hui-Tian Wang

Physics & Astronomy Faculty Research

A computational methodology based on ab initio evolutionary algorithms and spin-polarized density functional theory was developed to predict two-dimensional magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A metastable borophene with nonzero thickness is an antiferromagnetic semiconductor from first-principles calculations, and can be further tuned into a half-metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for magnetism, but also result in an out-of-plane negative Poisson's ratio under uniaxial tension, making it the first elemental material possessing auxetic and magnetic properties …