La3Ni4Al2: a new layered aluminide

2019 ◽  
Vol 234 (9) ◽  
pp. 581-586
Author(s):  
Nazar Zaremba ◽  
Yurij Schepilov ◽  
Galyna Nychyporuk ◽  
Viktor Hlukhyy ◽  
Volodymyr Pavlyuk
Keyword(s):  
Crystal Structure ◽  
Tight Binding ◽  
Orbital Method ◽  
Single Crystal Diffraction ◽  
Coordination Polyhedra ◽  
Atomic Sphere ◽  
X Ray ◽  
Square Prism ◽  
Sphere Approximation ◽  
Structure Calculations

Abstract The new ternary compound La3Ni4Al2 has been synthesized and the crystal structure has been studied by X-ray single crystal diffraction. La3Ni4Al2 is the first aluminide, crystallizing in the La3Ni4Ga2-type. The crystal structure of La3Ni4Al2 consists of La-layers and hetero-atomic Ni/Al layers, sequentially alternating along the a axis (pseudo-hexagonal c axis). According to electronic structure calculations using the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation (TB-LMTO-ASA), strong Al–Ni interactions have been established. The coordination polyhedra for the Al atoms are cuboctahedra, whereas the bicapped square prism and bicapped square antiprism are typical for nickel atoms. The lanthanum atoms are enclosed in pseudo Frank–Kasper polyhedra.

scholarly journals Disodium hydrogen citrate sesquihydrate, Na2HC6H5O7(H2O)1.5

2016 ◽  
Vol 72 (7) ◽  
pp. 943-946 ◽  
Author(s):  
Alagappa Rammohan ◽  
Amy A. Sarjeant ◽  
James A. Kaduk
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Single Crystal Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Carboxylic Acid Groups ◽  
Sodium Cations ◽  
Disodium Hydrogen Citrate

The crystal structure of disodium hydrogen citrate sesquihydrate, 2Na2+·C6H6O72−·1.5H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. The asymmetric unit contains two independent hydrogen citrate anions, four sodium cations and three water molecules. The coordination polyhedra of the cations (three with a coordination number of six, one with seven) share edges to form isolated 8-rings. The un-ionized terminal carboxylic acid groups form very strong hydrogen bonds to non-coordinating O atoms, with O...O distances of 2.46 Å.

ELECTRONIC STRUCTURE OF THE PEROVSKITE OXIDES SrCrO3 AND PbCrO3

1992 ◽  
Vol 06 (02) ◽  
pp. 103-112 ◽  
Author(s):  
S. MATHI JAYA ◽  
R. JAGADISH ◽  
R.S. RAO ◽  
R. ASOKAMANI
Keyword(s):  
Electronic Structure ◽  
Good Description ◽  
Perovskite Oxides ◽  
Orbital Method ◽  
Atomic Sphere ◽  
Calculated Magnetic Moment ◽  
Sphere Approximation ◽  
Quantitative Results ◽  
Structure Calculations ◽  
Good Agreement

The electronic structure calculations of the perovskite oxides SrCrO 3 and PbCrO 3 performed both in the paramagnetic and antiferromagnetic phases are reported here. The calculations were carried out using the Linear Muffin Tin Orbital method within the Atomic Sphere Approximation. The quantitative results obtained are found to give a good description of the electronic states of SrCrO 3 and are in agreement with the Goodenough’s qualitative chemical picture. However, it is not able to predict the semiconducting gap in PbCrO 3 which is an antiferromagnetic semiconductor. But the value of the theoretically calculated magnetic moment at the Cr site in PbCrO 3 is found to be in good agreement with the experimentally observed value. The calculations show strong hybridisation between the Cr -3d and O -2p orbitals and the density of states at the Fermi energy has major contributions from these hybridised orbitals.

scholarly journals Study of Electronic and Magnetic Properties of CuPd, CuPt, Cu3Pd and Cu3Pt: Tight Binding Linear Muffin-Tin Orbitals Approach

2015 ◽  
Vol 19 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Shiva Dahal ◽  
Gyanu Kafle ◽  
Gopi Chandra Kaphle ◽  
Narayan Prasad Adhikari
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Tight Binding ◽  
Atomic Sphere ◽  
Band Structure Calculations ◽  
Ordered Alloys ◽  
Sphere Approximation ◽  
Atomic Sphere Approximation ◽  
Structure Calculations ◽  
Magnetic Nature

Electronic structure of ordered alloys CuPd, CuPt, Cu3Pd and Cu3Pt have been studied using Tight Binding Linear Muffin-Tin Orbitals Atomic Sphere Approximation (TB-LMTO-ASA). For the electronic properties, we have performed band structure calculations. Our findings show that all the systems considered are metallic in nature. To know the contribution of the orbitals in the bands, the system is analyzed via fat bands which reveal most of the contributions on valence band for CuPd, CuPt, Cu3Pd and Cu3Pt is from d-orbital and on conduction band is from s and p-orbitals. We have also checked the magnetic properties of the alloys. The density of states for spin up and spin down electrons have found to be same in each and every steps, showing non-magnetic nature of CuPd, CuPt, Cu3Pd and Cu3Pt.Journal of Institute of Science and Technology, 2014, 19(1): 137-144

LiBC3: a new borocarbide based on graphene and heterographene networks

2017 ◽  
Vol 73 (11) ◽  
pp. 984-989 ◽  
Author(s):  
Viktoria Milashius ◽  
Volodymyr Pavlyuk ◽  
Karolina Kluziak ◽  
Grygoriy Dmytriv ◽  
Helmut Ehrenberg
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Tight Binding ◽  
Lithium Ion ◽  
Electronic Structure Calculations ◽  
Structure Type ◽  
Coordination Polyhedra ◽  
Carbon Networks ◽  
Structure Calculations ◽  
Potential Use

Li–B–C alloys have attracted much interest because of their potential use in lithium-ion batteries and superconducting materials. The formation of the new compound LiBC3 [lithium boron tricarbide; own structure type, space group P\overline{6}m2, a = 2.5408 (3) Å and c = 7.5989 (9) Å] has been revealed and belongs to the graphite-like structure family. The crystal structure of LiBC3 presents hexagonal graphene carbon networks, lithium layers and heterographene B/C networks, alternating sequentially along the c axis. According to electronic structure calculations using the tight-binding linear muffin-tin orbital-atomic spheres approximations (TB–LMTO–ASA) method, strong covalent B—C and C—C interactions are established. The coordination polyhedra for the B and C atoms are trigonal prisms and for the Li atoms are hexagonal prisms.

scholarly journals Tricaesium citrate monohydrate, Cs3C6H5O7·H2O: crystal structure and DFT comparison

2017 ◽  
Vol 73 (4) ◽  
pp. 520-523 ◽  
Author(s):  
Alagappa Rammohan ◽  
Amy A. Sarjeant ◽  
James A. Kaduk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Density Functional ◽  
Three Dimensional ◽  
Carboxylate Group ◽  
Single Crystal Diffraction ◽  
Coordination Polyhedra ◽  
X Ray

The crystal structure of tricaesium citrate monohydrate, 3Cs+·C6H5O73−·H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. This compound is isostructural to the K+and Rb+compounds with the same formula. The three independent Cs cations are eight-, eight-, and seven-coordinate, with bond-valence sums of 0.91, 1.22, and 1.12 valence units. The coordination polyhedra link into a three-dimensional framework. The hydroxy group forms the usualS(5) hydrogen bond with the central carboxylate group, and the water molecule acts as a donor in two strong hydrogen bonds.

Crystal structure characterization and electronic structure of a rare-earth-containing Zintl phase in the Yb–Al–Sb family: Yb3AlSb3

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Rongqing Shang ◽  
An T. Nguyen ◽  
Allan He ◽  
Susan M. Kauzlarich
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Rare Earth ◽  
Electronic Structure Calculations ◽  
Structure Characterization ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Zintl Phase ◽  
X Ray ◽  
Structure Calculations

A rare-earth-containing compound, ytterbium aluminium antimonide, Yb3AlSb3 (Ca3AlAs3-type structure), has been successfully synthesized within the Yb–Al–Sb system through flux methods. According to the Zintl formalism, this structure is nominally made up of (Yb2+)3[(Al1−)(1b – Sb2−)2(2b – Sb1−)], where 1b and 2b indicate 1-bonded and 2-bonded, respectively, and Al is treated as part of the covalent anionic network. The crystal structure features infinite corner-sharing AlSb4 tetrahedra, [AlSb2Sb2/2]6−, with Yb2+ cations residing between the tetrahedra to provide charge balance. Herein, the synthetic conditions, the crystal structure determined from single-crystal X-ray diffraction data, and electronic structure calculations are reported.

scholarly journals Synthesis, Characterization, and Crystal Structure of [Co4(CH3CO2)2L4]2[BPh4]4·0.5H2O, Where HL = 4-(Salicylaldiminato)antipyrine

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ramadan M. El-mehdawi ◽  
Abdussalam N. EL-dewik ◽  
Mufida M. Ben-Younes ◽  
Fathia A. Treish ◽  
Ramadan G. Abuhmaiera ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Schiff Base ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Schiff Base Ligand ◽  
Title Complex ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Tridentate Schiff Base

The title complex was isolated as a red solid from the reaction of 4-(salicylaldiminato)antipyrine, HL, and cobalt (II) acetate in ethanol. The complex has been characterized by elemental analysis, FTIR, UV-Vis, and X-ray single crystal diffraction. Two crystallographically different cationic units, A and B, of the title complex are found. Both units are essentially isostructural; nevertheless, small differences exist between them. Both units contain four cobalt atoms arranged at the corners of distorted cubane-like core alternatively with phenoxy oxygen of the Schiff base. In both cases, one cobalt binds to three coordinated sites from the corresponding tridentate Schiff base ligand, and the fourth one was bonded by the acetate oxygen, and the fifth and the sixth donor sites come from the phenolate oxygen of another Schiff base ligand.

The Transition Metal-rich Orthophosphate Arrojadite with Special Structural Features

2010 ◽  
Vol 65 (12) ◽  
pp. 1427-1433 ◽  
Author(s):  
Christoph Kallfaß ◽  
Constantin Hoch ◽  
Hermann Schier ◽  
Arndt Simon ◽  
Helmut Schuber
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Single Crystal ◽  
Structural Features ◽  
Nickel Plate ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Different Types ◽  
New Feature

The crystal structure of the transition metal-rich orthophosphate mineral arrojadite was reexamined, and the disorder phenomena were analyzed applying modern X-ray single-crystal diffraction and refinement methods on samples from Nickel Plate (USA) and Hagendorf (Germany). As a new feature of the arrojadite structure, two different types of channels oriented along [010] are described. The occupancy of the atomic positions inside these channels have been elucidated.

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