The Ce2Li0.39Ni1.61Si2structure as a new derivative of the AlB2family

2014 ◽  
Vol 70 (6) ◽  
pp. 622-626 ◽  
Author(s):  
Andrij Stetskiv ◽  
Beata Rozdzynska-Kielbik ◽  
Volodymyr Pavlyuk
Keyword(s):  
Intermetallic Compounds ◽  
Title Compound ◽  
Classification Scheme ◽  
Tight Binding ◽  
Structure Type ◽  
Vertex Polyhedron ◽  
Orbital Method ◽  
Crystal Chemical ◽  
Nickel Disilicide ◽  
Metallic Bonding

A new quaternary dicerium lithium/nickel disilicide, Ce2Li0.39Ni1.61Si2, crystallizes as a new structure type of intermetallic compounds closely related to the AlB2family. The crystal–chemical interrelationships between parent AlB2-type, BaLiSi, ZrBeSi and the title compound are discussed using the Bärnighausen formalism. Two Ce atoms occupy sites of 3m. symmetry. The remainder,i.e.Ni, mixed Ni/Li and Si atoms, occupy sites of \overline{6}m2 symmetry. The environment of the Ce atom is an 18-vertex polyhedron and the Ni, Ni/Li and Si atoms are enclosed in tricapped trigonal prisms. The title structure can be assigned to class No. 10 (trigonal prism and its derivatives) according to the Krypyakevich classification scheme [Krypyakevich (1977). InStructure Types of Intermetallic Compounds. Moscow: Nauka]. The electronic structure of the title compound was calculated using the tight-binding linear muffin-tin orbital method in the atomic spheres approximation (TB-LMTO-ASA). Metallic bonding is dominant in this compound. The strongest interactions are Ni—Si and Ce—Si.

Tm2.22Co6Sn20and TmLi2Co6Sn20stannides as disordered derivatives of the Cr23C6structure type

2013 ◽  
Vol 69 (7) ◽  
pp. 683-688 ◽  
Author(s):  
Andrij Stetskiv ◽  
Beata Rozdzynska-Kielbik ◽  
Volodymyr Pavlyuk
Keyword(s):  
Electronic Structures ◽  
Ternary Phase ◽  
Tight Binding ◽  
Structure Type ◽  
Vertex Polyhedron ◽  
Orbital Method ◽  
Hexagonal Prism ◽  
The Third ◽  
Metallic Bonding ◽  
Derivatives Of

A new ternary dithulium hexacobalt icosastannide, Tm2.22Co6Sn20, and a new quaternary thulium dilithium hexacobalt icosastannide, TmLi2Co6Sn20, crystallize as disordered variants of the binary cubic Cr23C6structure type (cF116). 48 Sn atoms occupy sites ofm.m2 symmetry, 32 Sn atoms sites of .3msymmetry, 24 Co atoms sites of 4m.msymmetry, eight Li (or Tm in the case of the ternary phase) atoms sites of \overline{4} 3m symmetry and four Tm atoms sites of m \overline{3} m symmetry. The environment of one Tm atom is an 18-vertex polyhedron and that of the second Tm (or Li) atom is a 16-vertex polyhedron. Tetragonal antiprismatic coordination is observed for the Co atoms. Two Sn atoms are enclosed in a heavily deformed bicapped hexagonal prism and a monocapped hexagonal prism, respectively, and the environment of the third Sn atom is a 12-vertex polyhedron. The electronic structures of both title compounds were calculated using the tight-binding linear muffin-tin orbital method in the atomic spheres approximation (TB–LMTO–ASA). Metallic bonding is dominant in these compounds, but the presence of Sn—Sn covalent dumbbells is also observed.

Ternary Scandium-rich Indides Sc50T13In3 and Sc50Rh13In3Oy (T = Rh, Ir; y ≈ 8) – Synthesis and Crystal Structure

2007 ◽  
Vol 62 (12) ◽  
pp. 1567-1573 ◽  
Author(s):  
Roman Zaremba ◽  
Rainer Pöttgen
Keyword(s):  
Crystal Structure ◽  
Intermetallic Compounds ◽  
Induction Furnace ◽  
Structure Type ◽  
Crystal Chemical ◽  
Synthesis And Crystal Structure ◽  
Sample Chamber ◽  
Cubic Structure ◽  
Scandium Content ◽  
Tetrahedral Voids

New intermetallic compounds Sc50Rh13.3In2.7 and Sc50Ir13.6In2.4 and the suboxides Sc49.2Rh13In3.8O8.8 and Sc49.2Rh13.7In2.8O8.0 were synthesized from the elements or with Sc2O3 as an oxygen source, respectively, in sealed tantalum tubes in a water-cooled sample chamber of an induction furnace. They crystallize with a new cubic structure type, space group Fm3̅, a = 1772.5(6) pm, wR2 = 0.032, 1111 F2 values, 34 variables for Sc50Rh13.3In2.7, a = 1766.5(6) pm, wR2 = 0.041, 745 F2 values, 34 variables for Sc50Ir13.6In2.4, a = 1764.4(2) pm, wR2 = 0.044, 690 F2 values, 41 variables for Sc49.2Rh13In3.8O8.8, and a = 1761.5(6) pm, wR2 = 0.054, 740 F2 values, 42 variables for Sc49.2Rh13.7In2.8O8.0. The main structural motifs are rhodium-centered indium cubes in an fcc like arrangement in which the octahedral and tetrahedral voids are filled by In2Sc12 and In1Sc12 icosahedra, respectively, resembling a Li3Bi-like structure. The Rh1 (Ir1) and Sc4 atoms lie between these polyhedral units. The oxygen atoms partially fill Sc6 octahedra in Sc49.2Rh13In3.8O8.8 and Sc49.2Rh13.7In2.8O8.0 with Sc-O distances of 214 - 230 pm. These octahedra are condensed via common edges and faces, encapsulating the In2Sc12 icosahedra. Due to the high scandium content one observes strong Sc-Sc bonding with Sc-Sc distances ranging from 303 to 362 pm in Sc49.2Rh13In3.8O8.8. The shortest distances occur for Sc-Rh (267 - 295 pm). The crystal chemical relationship with the Li3Bi-related suboxide Ti12Sn3O10 is discussed.

A new tetragonal structure type for Li2B2C

2015 ◽  
Vol 71 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Volodymyr Pavlyuk ◽  
Viktoriya Milashys ◽  
Grygoriy Dmytriv ◽  
Helmut Ehrenberg
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Structure Type ◽  
Tetragonal Structure ◽  
Vertex Polyhedron ◽  
Coordination Polyhedra ◽  
Space Group ◽  
Nearest Neighbours ◽  
Structure Calculations ◽  
Lateral Facet

The ternary dilithium diboron carbide, Li2B2C (tetragonal, space groupP\overline{4}m2,tP10), crystallizes as a new structure type and consists of structural fragments which are typical for structures of elemental lithium and boron or binary borocarbide B13C2. The symmetries of the occupied sites are .m. and 2mm. for the B and C atoms, and \overline{4}m2 and 2mm. for the Li atoms. The coordination polyhedra around the Li atoms are cuboctahedra and 15-vertex distorted pseudo-Frank–Kasper polyhedra. The environment of the B atom is a ten-vertex polyhedron. The nearest neighbours of the C atom are two B atoms, and this group is surrounded by a deformed cuboctahedron with one centred lateral facet. Electronic structure calculations using the TB–LMTO–ASA method reveal strong B...C and B...B interactions.

scholarly journals Crystal structure of guanidinium hexafluoridovanadate(III), (CN3H6)3[VF6]: an unusual hybrid compound related to perovskite

2017 ◽  
Vol 73 (3) ◽  
pp. 244-246 ◽  
Author(s):  
Cameron Black ◽  
Philip Lightfoot
Keyword(s):  
Crystal Structure ◽  
Physical Properties ◽  
Title Compound ◽  
Crystal Chemical ◽  
Hybrid Compound ◽  
Structure Space ◽  
Perovskite Materials ◽  
Synthetic Routes ◽  
Cubic Structure ◽  
Covalent Interactions

Vanadium fluorides with novel crystal–chemical features and interesting physical properties can be prepared by solvothermal synthetic routes. The title compound, guanidinium hexafluoridovanadate(III), has a cubic structure (space group Pa\overline{3}), exhibiting isolated regular VF6 octahedral units, which are hydrogen bonded to protonated guanidinium moieties. Although the VF6 octahedral units are not linked directly together, there are structural similarities between this crystal structure and those of the wider family of perovskite materials, in particular, hybrid perovskites based on extended ligands such as cyanide. In this context, the octahedral tilt system of the present compound is of interest and demonstrates that unusual tilt systems can be mediated via `molecular' linkers which allow only supramolecular rather than covalent interactions.

A new stacking variant of Na2Pt(OH)6

2018 ◽  
Vol 73 (11) ◽  
pp. 831-836 ◽  
Author(s):  
Gohil S. Thakur ◽  
Hans Reuter ◽  
Claudia Felser ◽  
Martin Jansen
Keyword(s):  
Oxygen Pressure ◽  
Title Compound ◽  
Structure Type ◽  
Direct Reaction ◽  
Solid Residue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Edge Distance ◽  
Naoh Solution

AbstractA new stacking variant of sodium hexa-hydroxo platinate(IV), Na2Pt(OH)6, was synthesized and its structure elucidated through X-ray diffraction. The new polymorph was prepared by direct reaction of PtO2 with an excess of NaOH solution applying elevated oxygen pressure at 300°C. The structure consists of layers of edge sharing Pt(OH)6 and Na(OH)6 octahedra. These layers are separated by an edge-to-edge distance of ~2.4 Å. The packing of the hydroxide ions corresponds to the hcp sequence, the title compound thus may be regarded a cation ordered variant of the Brucite structure type. During heating above T~300°C all constitutional water is released, and anhydrous Na2PtO3 remains as the solid residue.

Neue intermetallische Verbindungen im anti-PbFCl-Strukturtyp.

1976 ◽  
Vol 31 (8) ◽  
pp. 1050-1052 ◽  
Author(s):  
Wolfgang Dörrscheidt ◽  
Herbert Schäfer
Keyword(s):  
Intermetallic Compounds ◽  
Structure Type

Three new intermetallic compounds CaMnGe, SrMnGe and BaMnGe have been prepared. They crystallize tetragonal in the anti-PbFCl-structure type with the following constants :CaMnGe: a = 4.23(1); c = 7.27(1); c/a = 1.72,SrMnGe: a = 4.40(1); c = 7.52(1); c/a = 1.71,BaMnGe: a = 4.50(1); c = 7.92(1); c/a = 1.76.

A new ternary silicide GdFe1−xSi2 (x=0.32): preparation, crystal and electronic structure

2020 ◽  
Vol 75 (1-2) ◽  
pp. 217-223
Author(s):  
Volodymyr Babizhetskyy ◽  
Jürgen Köhler ◽  
Yuriy Tyvanchuk ◽  
Chong Zheng
Keyword(s):  
Electronic Structure ◽  
Tight Binding ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Lmto Method ◽  
Type Orthorhombic ◽  
Crystal And Electronic Structure

AbstractThe title compound was prepared from the elements by arc-melting. The crystal structure was investigated by means of single-crystal X-ray diffraction. It crystallizes in the TbFeSi2 structure type, orthorhombic space group Cmmm, a = 4.0496(8), b = 16.416(2), c = 3.9527(6) Å, Z = 4, R1 = 0.041, wR2 = 0.11 for 207 unique reflections with Io > 2 σ(Io) and 19 refined parameters. The Fe position is not fully occupied and the refinement results in a composition GdFe0.68Si2 in agreement with a chemical analysis. The structure consists of zig-zag chains of Si(1) atoms which are terminally bound to additional Si(2) atoms. For an ordered variant GdFe0.5Si2 the Zintl concept can be applied which results in formal oxidation states Gd3+(Fe2+)0.5Si(1)1−Si(2)3−. The electronic structure of this variant GdFe0.5Si2 was analyzed using the tight-binding LMTO method and the results confirm the simple bonding picture.

scholarly journals Structure feature of ternary state diagrams of Cr-Ti-V and Cr-Mn-V systems

2018 ◽  
Vol 243 ◽  
pp. 00014 ◽  
Author(s):  
Anatoliy Klopotov ◽  
Irina Kurzina ◽  
Alexander Potekaev ◽  
Artem Ustinov ◽  
Taras Dement ◽  
...  
Keyword(s):  
Solid Solution ◽  
Intermetallic Compounds ◽  
Solid Solutions ◽  
Crystal Chemical ◽  
Electron Number ◽  
Isothermal Sections ◽  
State Diagrams ◽  
Bcc Lattice ◽  
Existence Domain ◽  
Chemical Factors

This paper presents the research results of features of structural and phase states in Cr-Ti-V and Cr-Mn-V systems based on analysis of crystal-geometric and crystal-chemical factors. The diagrams of isothermal sections of state diagrams of Cr-Ti-V and Cr-Mn-V systems were built in coordinates of the electron number (s+d) per atom with homogeneity regions of solid solutions and intermetallic compounds. It was shown that in the Cr-Ti-V system, addition of Mn atoms leads to substantial extension of the existence domain of the disordered solid solution based on the BCC lattice.

The fragment molecular orbital method combined with density-functional tight-binding and the polarizable continuum model

2016 ◽  
Vol 18 (32) ◽  
pp. 22047-22061 ◽  
Author(s):  
Yoshio Nishimoto ◽  
Dmitri G. Fedorov
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Continuum Model ◽  
Density Functional ◽  
Tight Binding ◽  
Polarizable Continuum Model ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Polarizable Continuum ◽  
Structure Of Proteins

The electronic gap in proteins is analyzed in detail, and it is shown that FMO-DFTB/PCM is efficient and accurate in describing the molecular structure of proteins in solution.

Sign in / Sign up

Export Citation Format

Share Document