scholarly journals Crystal Structures of Al2Cu Revisited: Understanding Existing Phases and Exploring Other Potential Phases

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1037 ◽  
Author(s):  
Sai Wang ◽  
Changzeng Fan
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Single Crystal ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Relationships ◽  
Al2cu Phase ◽  
High Pressure Sintering

When processing single crystal X-ray diffraction datasets for twins of Al2Cu sample synthesized by the high-pressure sintering (HPS) method, we have clarified why the crystal structure of Al2Cu was incorrectly solved about a century ago. The structural relationships between all existing Al2Cu phases, including the Owen-, θ-, θ’-, and Ω-Al2Cu phases, were investigated and established based on a proposed pseudo Al2Cu phase. Two potential phases have been built up by adjusting the packing sequences of A/B layers of Al atoms that were inherent in all existing Al2Cu phases. The mechanical, thermal, and dynamical stability of two such novel phases and their electronic properties were investigated by first-principles calculations.

scholarly journals Structure and Stability of the Stoichiometric Al3Fe Phase

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1322
Author(s):  
Zheng Xia ◽  
Bin Wen ◽  
Changzeng Fan
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Enthalpy Of Formation ◽  
First Principles ◽  
First Principles Calculations ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

A disordered stoichiometric Al3Fe phase was obtained when synthesizing Al8Fe3 by the spark plasma sintering (SPS) approach and its crystal structure was determined by the single-crystal X-ray diffraction (SXRD) techniques. The refined structure is an isotype of the reported Al5Fe2 phase, only different in the site occupation factors (s. o. f.) of Al2 and Al3 atoms, which was refined to be 0.431 (13) and 0.569 (13), respectively. Stimulated by the structural refinement results, an ordered stoichiometric Al3Fe phase was established. First-principles calculations reveal that the ordered Al3Fe phase is mechanically and dynamically stable and has a much lower value of enthalpy of formation than any other proposed Al3Fe phases, although it is also metallic and metastable.

Structural analysis of Gd6FeBi2 from single-crystal X-ray diffraction methods and electronic structure calculations

2019 ◽  
Vol 75 (5) ◽  
pp. 562-567 ◽  
Author(s):  
Jiliang Zhang ◽  
Yong-Mook Kang ◽  
Guangcun Shan ◽  
Svilen Bobev
Keyword(s):  
Electronic Structure ◽  
Single Crystal ◽  
First Principles ◽  
Earth Metal ◽  
Magnetic Ordering ◽  
Additional Contribution ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
Magnetic Exchange ◽  
X Ray

The crystal structure of the gadolinium iron bismuthide Gd6FeBi2 has been characterized by single-crystal X-ray diffraction data and analyzed in detail using first-principles calculations. The structure is isotypic with the Zr6CoAl2 structure, which is a variant of the ZrNiAl structure and its binary prototype Fe2P (Pearson code hP9, Wyckoff sequence g f d a). As such, the structure is best viewed as an array of tricapped trigonal prisms of Gd atoms centered alternately by Fe and Bi. The magnetic-ordering temperature of this compound (ca 350 K) is much higher than that of other rare-earth metal-rich phases with the same or related structures. It is also higher than the ordering temperature of many other Gd-rich ternary phases, where the magnetic exchange is typically governed by Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions. First-principles calculations reveal a larger than expected Gd magnetic moment, with the additional contribution arising from the Gd 5d electrons. The electronic structure analysis suggests strong Gd 5d–Fe 3d hybridization to be the cause of this effect, rather than weak interactions between Gd and Bi. These details are of importance for understanding the magnetic response and explaining the high ordering temperature in this material.

Study of Phase Transformation in BaTe2O6 by in Situ High-Pressure X-ray Diffraction, Raman Spectroscopy, and First-Principles Calculations

2015 ◽  
Vol 55 (1) ◽  
pp. 227-238 ◽  
Author(s):  
K. K. Mishra ◽  
S. Nagabhusan Achary ◽  
Sharat Chandra ◽  
T. R. Ravindran ◽  
K. K. Pandey ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Phase Transformation ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
X Ray

Notizen: Zur Kristallstruktur von SrPbO3 / The Crystal Structure of SrPbO3

1975 ◽  
Vol 30 (3-4) ◽  
pp. 277-278 ◽  
Author(s):  
Hans-L. Keller ◽  
Karl-H. Meier ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Pressure Synthesis ◽  
Group D

Single crystals of SrPbO3 could be prepared by oxygen-high-pressure-synthesis (PO2 > 3500 at, t = 450°C). Single crystal X-ray diffraction data confirm the space group D2h16-Pnma. SrPbO3 belongs to the orthorhombic distorted Perowskit type with a = 5.964, b = 8.320, c = 5.860 Å. The atomic positions were refined.

High-temperature, high-pressure hydrothermal synthesis, crystal structure and photoluminescent properties, of K3[Gd1−xTbxGe3O8(OH)2] (x = 0, 0.3, 0.1, 1)

RSC Advances ◽  
2014 ◽  
Vol 4 (51) ◽  
pp. 26951-26955 ◽  
Author(s):  
Wei Liu ◽  
Min Yang ◽  
Ying Ji ◽  
Fuyang Liu ◽  
Ying Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Hydrothermal Synthesis ◽  
Single Crystal ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature High Pressure

A family of new lanthanide germanates K3LnGe3O8(OH)2 have been synthesized by a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction.

Synthesis, crystal structure, and luminescence properties of a new microporous europium silicate: Na3EuSi6O15·1.47H2O

RSC Advances ◽  
2015 ◽  
Vol 5 (37) ◽  
pp. 29121-29125 ◽  
Author(s):  
Wei Liu ◽  
Ying Ji ◽  
Fuyang Liu ◽  
Min Yang ◽  
Ying Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Single Crystal ◽  
Xrd Analysis ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
X Ray

A new microporous europium silicate, Na3EuSi6O15·1.47H2O (denoted as 1), was synthesized under high-temperature and high-pressure conditions, and structurally characterized by single-crystal and powder X-ray diffraction (XRD) analysis.

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