Tetrahedrally bonded ternary and quasi-binary compounds general remarks on crystal structure and related properties

2005 ◽  
pp. 1-8
Author(s):  
Keyword(s):  
Crystal Structure ◽  
Binary Compounds ◽  
Tetrahedrally Bonded

Über einige Beziehungen zwischhen Kristallstrukturen

1956 ◽  
Vol 11 (11) ◽  
pp. 920-934b
Author(s):  
Konrad Schubert
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Spatial Correlation ◽  
Chemical Elements ◽  
Electron Gas ◽  
Lattice Constants ◽  
Hexagonal Close Packed ◽  
Binary Compounds ◽  
Atomic Radii ◽  
Insight Into

In determining structures we use physical propositions in order to find a likely crystal structure. The same propositions are of value for the ordering of known structures into a natural system. The atomic radii form such a proposition. Another proposition is contained in the spatial correlation of electrons in the electron gas. The question is, whether this correlation is of influence on the crystal structure or not. To gain a first insight into this question, it is useful to know whether the crystal structures are physically compatible with a certain spatial correlation of electrons. Some qualitative rules are given to assess the physical possibility of a spatial correlation of electrons in a crystal structure. For the crystal structures of some chemical elements proposals for electron correlation are given. These proposals account for rationalities existing between some lattice constants, e. g. the axial ratios of the hexagonal close packed structures of Co and Zn. The proposals are also applicable to some binary compounds. With regard to these commensurabilities, it seems possible that the examination of the spatial correlation of electrons may lead to a better understanding of the crystal-chemical empiry.

scholarly journals Darstellung und Kristallstruktur von K2Sn2S5 und K2Sn2Se5 / Preparation and Crystal Structure of K2Sn2S5 and K2Sn2Se5

1992 ◽  
Vol 47 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Kurt O. Klepp
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structure Type ◽  
Slow Cooling ◽  
Bond Lengths ◽  
Trigonal Bipyramidal ◽  
Equatorial Bond ◽  
Binary Compounds ◽  
R Factors ◽  
Distorted Trigonal Bipyramidal

K2Sn2S5 and K2Sn2Se5 were prepared by reacting stoichiometric powdered mixtures of the binary compounds K2S or K2Se with Sn and the corresponding chalcogen at 1070 K, followed by slow cooling of the melt. The two compounds are isostructural and crystallize with the Tl2Sn2S5 structure type, s.g. C 2/c, Z = 4 with a = 11.072(5) Å, b = 7.806(3)Å, c = 11.517(5)Å, β = 108.43(2)° for K2Sn2S5 and a = 11.613(5)Å, b = 8.189(3) Å, c = 11,897(6) Å, β = 108.28(2)° for K2Sn2Se5. The crystal structures were refined to conventional R-factors of 0.032 and 0.031, respectively. Sn-atoms are in a distorted trigonal-bipyramidal chalcogen coordination. The average equatorial bond lengths are Sn -S: 2.427 Å and Sn -Se: 2.552 Å , the axial ones are Sn -S: 2.600 Å and Sn -Se: 2.774 Å.

scholarly journals The Ti-Fe-P system: phase equilibria and crystal structure of phases

2013 ◽  
Vol 11 (9) ◽  
pp. 1518-1526 ◽  
Author(s):  
Oksana Toma ◽  
Mariya Dzevenko ◽  
Anton Oliynyk ◽  
Yaroslava Lomnytska
Keyword(s):  
Crystal Structure ◽  
Phase Equilibria ◽  
Stoichiometric Composition ◽  
P System ◽  
Single Crystal Diffraction ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Binary Compounds ◽  
System Phase

AbstractAbstract Phase equilibria was investigated in the Ti-Fe-P system at T = 1070 K in the region 0–67 at.% of P, employing X-ray powder diffraction. The two ternary compounds, namely Ti0.5–0.8Fe1.5−1.2P (Co2Si-type; space group Pnma; a = 0.5964(2)–0.6011(3), b = 0.3575(3)–0.3600(1), c = 0.6828(2)–0.6882(2) nm) and Ti0.85−1.25Fe1.15−0.75P (ZrNiAl-type; space group P-62m; a = 0.6071(4)–0.6117(1), c = 0.3510(9)–0.3506(1) nm) exist in the Ti-Fe-P system at this temperature. The crystal structure of the Ti0.85–1.25Fe1.15−0.75P compound was additionally determined by X-ray single crystal diffraction on the phase with stoichiometric composition. The substitutions of Ti by Fe were observed for Ti5P3.16, Ti3P and TiP phases, and Fe for Ti in the case of Fe3P, Fe2P binary compounds. Graphical abstract

Synthesis of New Thermoelectrics Using Modulated Elemental Reactants

1997 ◽  
Vol 478 ◽  
Author(s):  
Marc D. Hornbostel ◽  
Heike Sellinschegg ◽  
David C. Johnson
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Systematic Screening ◽  
X Ray ◽  
Low Temperature Annealing ◽  
Modulated Elemental Reactants ◽  
Ternary Metal ◽  
Elemental Reactants ◽  
Binary Compounds ◽  
New Compounds

AbstractA series of new, metastable ternary crystalline compounds with the skutterudite crystal structure have been synthesized using modulated elemental reactants. The initial reactants are made up of multiple repeats of a ˜25Å thick unit containing elemental layers of the desired ternary metal, iron and antimony. Low temperature annealing (150°C) results in interdiffusion of the elemental layers to form amorphous reaction intermediates. Annealing these intermediates at temperatures between 200°C and 250°C results in exothermic crystallization of the desired skutterudite crystal structure. Most of the new compounds prepared are only kinetically stable, decomposing exothermically to form thermodynamically more stable mixtures of binary compounds and elements. Low angle x-ray diffraction studies show that the resulting films are exceedingly smooth. These films have an ideal geometry for measuring properties of importance for thermoelectric devices—the Seebeck coefficient and the electrical conductivity. Thermal conductivity can be measured using a modification of the 3ω technique of Cahill. Samples can be produced rapidly, allowing for systematic screening and subsequent optimization as a function of composition and doping levels.

Synthese und Kristallstruktur von Pt2Sn2Zn3, der ersten ternären Verbindung im System Pt/Sn/Zn / Synthesis and Crystal Structure of Pt2Sn2Zn3, the First Ternary Compound of the Pt/Sn/Zn System

2006 ◽  
Vol 61 (7) ◽  
pp. 862-866 ◽  
Author(s):  
Rainer Lux ◽  
Harald Hillebrecht
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Single Crystals ◽  
Ternary Compound ◽  
Structure Type ◽  
Synthesis And Crystal Structure ◽  
Binary Compounds

Single crystals of Pt2Sn2Zn3, the first ternary compound in the system Pt/Sn/Zn, have been synthesised from the elements. Pt2Sn2Zn3 exhibits a new structure type (hP14, P63/mmc, Z = 2, a = 4.3367(5), c = 15.532(3) Å , 402 reflections, 14 variables, R1(F) = 0.025, wR2(I) = 0.059) with motifs of the binary compounds. One Pt atom has a cubic environment (PtSn6Zn2), the second one forms an Edshammer polyhedron (PtSn2Zn9). Pt2Sn2Zn3 is one of the few examples of a ternary Sn/Zn compound of a transition metal.

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