scholarly journals High-Pressure Synthesis and Chemical Bonding of Barium Trisilicide BaSi3

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 145 ◽  
Author(s):  
Julia-Maria Hübner ◽  
Lev Akselrud ◽  
Walter Schnelle ◽  
Ulrich Burkhardt ◽  
Matej Bobnar ◽  
...  
Keyword(s):  
High Pressure ◽  
Chemical Bonding ◽  
Ambient Pressure ◽  
Covalent Bonding ◽  
Partial Structure ◽  
Exothermal Reaction ◽  
Metallic Behavior ◽  
Bonding Analysis ◽  
Group I ◽  
Pressure Synthesis

BaSi3 is obtained at pressures between 12(2) and 15(2) GPa and temperatures from 800(80) and 1050(105) K applied for one to five hours before quenching. The new trisilicide crystallizes in the space group I 4 ¯ 2m (no. 121) and adopts a unique atomic arrangement which is a distorted variant of the CaGe3 type. At ambient pressure and 570(5) K, the compound decomposes in an exothermal reaction into (hP3)BaSi2 and two amorphous silicon-rich phases. Chemical bonding analysis reveals covalent bonding in the silicon partial structure and polar multicenter interactions between the silicon layers and the barium atoms. The temperature dependence of electrical resistivity and magnetic susceptibility measurements indicate metallic behavior.

scholarly journals A chemical perspective on high pressure crystal structures and properties

2019 ◽  
Vol 7 (1) ◽  
pp. 149-169 ◽  
Author(s):  
John S Tse
Keyword(s):  
High Pressure ◽  
Crystal Structures ◽  
Chemical Bonding ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
New Era ◽  
Group I ◽  
Open Structures ◽  
Powder Samples ◽  
General Expectation

Abstract The general availability of third generation synchrotron sources has ushered in a new era of high pressure research. The crystal structure of materials under compression can now be determined by X-ray diffraction using powder samples and, more recently, from multi-nano single crystal diffraction. Concurrently, these experimental advancements are accompanied by a rapid increase in computational capacity and capability, enabling the application of sophisticated quantum calculations to explore a variety of material properties. One of the early surprises is the finding that simple metallic elements do not conform to the general expectation of adopting 3D close-pack structures at high pressure. Instead, many novel open structures have been identified with no known analogues at ambient pressure. The occurrence of these structural types appears to be random with no rules governing their formation. The adoption of an open structure at high pressure suggested the presence of directional bonds. Therefore, a localized atomic hybrid orbital description of the chemical bonding may be appropriate. Here, the theoretical foundation and experimental evidence supporting this approach to the elucidation of the high pressure crystal structures of group I and II elements and polyhydrides are reviewed. It is desirable and advantageous to extend and apply established chemical principles to the study of the chemistry and chemical bonding of materials at high pressure.

scholarly journals High-Pressure Synthesis of Non-Stoichiometric LixWO3 (0.5 ≤ x ≤ 1.0) with LiNbO3 Structure

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 63
Author(s):  
Kohdai Ishida ◽  
Yuya Ikeuchi ◽  
Cédric Tassel ◽  
Hiroshi Takatsu ◽  
Craig M. Brown ◽  
...  
Keyword(s):  
High Pressure ◽  
Perovskite Phase ◽  
Ambient Pressure ◽  
Tungsten Bronze ◽  
Type Structure ◽  
High Pressure Synthesis ◽  
Phase 0 ◽  
Pressure Synthesis ◽  
Octahedral Tilting ◽  
Recent Attention

Compounds with the LiNbO3-type structure are important for a variety of applications, such as piezoelectric sensors, while recent attention has been paid to magnetic and electronic properties. However, all the materials reported are stoichiometric. This work reports on the high-pressure synthesis of lithium tungsten bronze LixWO3 with the LiNbO3-type structure, with a substantial non-stoichiometry (0.5 ≤ x ≤ 1). Li0.8WO3 exhibit a metallic conductivity. This phase is related to an ambient-pressure perovskite phase (0 ≤ x ≤ 0.5) by the octahedral tilting switching between a−a−a− and a+a+a+.

High-Pressure Synthesis, Crystal Structure, and Properties of the New Orthorhombic Rare-Earth meta-Oxoborates RE(BO2)3 (RE = Dy – Lu)

2004 ◽  
Vol 59 (2) ◽  
pp. 202-215 ◽  
Author(s):  
Holger Emme ◽  
Tanja Nikelski ◽  
Thomas Schleid ◽  
Rainer Pöttgen ◽  
Manfred Heinrich Möller ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Ambient Pressure ◽  
Structure And Properties ◽  
Crystal Data ◽  
Temperature Conditions ◽  
Pressure Synthesis ◽  
Ir Spectroscopic ◽  
Pressure Phase

The new orthorhombic meta-oxoborates RE(BO2)3 (≡REB3O6) (RE = Dy-Lu) have been synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 °C. They are isotypic to the known ambient pressure phase Tb(BO2)3, space group Pnma. In contrast to Dy(BO2)3, which was also obtained in small amounts under high-temperature conditions, the preparation of the higher orthorhombic homologues RE(BO2)3 (RE = Ho-Lu) was only possible using high-pressure. The meta-oxoborates RE(BO2)3 (RE = Dy-Er) were synthesized as pure products, whereas the orthorhombic phases with RE = Tm-Lu were only obtained as byproducts. With the exception of Yb(BO2)3 it was possible to establish single crystal data for all compounds. The results of temperature-resolved in-situ powder-diffraction measurements, DTA, IR-spectroscopic investigations, and magnetic properties are also presented.

High-Pressure Synthesis and Crystal Structure of the New Orthorhombic Polymorph β-HgB4O7

2005 ◽  
Vol 60 (8) ◽  
pp. 815-820 ◽  
Author(s):  
Holger Emme ◽  
Matthias Weil ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ambient Pressure ◽  
Normal Pressure ◽  
High Pressure Phase ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
High Pressure Synthesis ◽  
Pressure Synthesis ◽  
Pressure Phase

The new orthorhombic polymorph β-HgB4O7 has been synthesized under high-pressure and hightemperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 600 °C. β-HgB4O7 is isotypic to the known ambient pressure phases MB4O7 (M = Sr, Pb, Eu) and the high-pressure phase β-CaB4O7 crystallizing with two formula units in the space group Pmn21 with lattice parameters a = 1065.6(2), b = 438.10(9), and c = 418.72(8) pm. The relation of the crystal structure of the high-pressure phase β-HgB4O7 to the normal pressure phase α-HgB4O7 as well as the relation to the isotypic phases MB4O7 (M = Sr, Pb, Eu) and β-CaB4O7 are discussed.

Notizen: Hochdrucksynthese und Einkristall-Strukturverfeinerung von Calciumaurat(III), CaAu2O4 / High Pressure Synthesis and Single-Crystal Structure Refinement of Calcium Aurate (III), CaAu2O4

1996 ◽  
Vol 51 (5) ◽  
pp. 747-750 ◽  
Author(s):  
Anja Louzikova ◽  
Klaus-Jürgen Range
Keyword(s):  
High Pressure ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Pressure Treatment ◽  
Partial Structure ◽  
High Pressure Treatment ◽  
Square Planar ◽  
Ca Ions ◽  
Pressure Synthesis ◽  
Type Apparatus

Single crystals of calcium aurate(III), CaAu2O4, were obtained by high-pressure treatment of a CaO/Au2O3/KO2 mixture at 40 kbar, 1200 °C in a modified Belt-type apparatus. The crystals are tetragonal, space group I41/a, with a = 5.9868(7), c = 10.043(1) Å, c/a = 1.678 and Z = 4.CaAu2O4 is isostructural with LaPd2O4, SrAu2O4 and BaAu2O4. Its structure comprises square-planar AuO4 groups (< Au-O > = 2.007 Å), which are stacked into columns along [100] and [010], These columns are connected by shared corners forming a three-dimensional framework. The Ca ions are situated in tunnels created by the gold-oxygen partial structure. They are surrounded by eight oxygen atoms (<Ca-O> = 2.490 Å) in a slightly distorted dodecahedron.

Lutetium Trigermanide LuGe3: High-Pressure Synthesis, Superconductivity, and Chemical Bonding

2018 ◽  
Vol 57 (16) ◽  
pp. 10295-10302 ◽  
Author(s):  
Julia-Maria Hübner ◽  
Matej Bobnar ◽  
Lev Akselrud ◽  
Yurii Prots ◽  
Yuri Grin ◽  
...  
Keyword(s):  
High Pressure ◽  
Chemical Bonding ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

High-Pressure Synthesis, Crystal Structure, Chemical Bonding, and Ferroelectricity of LiNbO3-Type LiSbO3

2018 ◽  
Vol 57 (24) ◽  
pp. 15462-15473 ◽  
Author(s):  
Yoshiyuki Inaguma ◽  
Akihisa Aimi ◽  
Daisuke Mori ◽  
Tetsuhiro Katsumata ◽  
Masanari Ohtake ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Chemical Bonding ◽  
High Pressure Synthesis ◽  
Pressure Synthesis
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