Die Kristallstruktur von Hf2Hg

Zusammenfassung Im System Hafnium-Quecksilber wurde im Temperaturbereich zwischen 500° C und 800° C nur eine Verbindung Hf₂Hg gefunden. Für diese Verbindung wird eine tetragonale Elementarzelle mita=3,34₅ Å,c=11,49₆ Å,c/a=3,436, Raumgruppe D _4h ¹⁷ –I 4/mmm vom MoSi₂-Typ vorgeschlagen.

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Investigations in the system hafnium—mercury have shown the existence of only one intermetallic compound Hf₂Hg. The structure is supposed to be tetragonal of the MoSi₂-type,a=3.34₅ Å,c=11.49₆ Å,c/a=3.436, belonging to the space group D _4h ¹⁷ –I 4/mmm.

     

Die Kristallstruktur von Zr2Al und Hf2Al

Zusammenfassung Im Zweistoff: Zr–Al bzw. Hf–Al werden zwei neue Kristallarten Zr₂Al und Hf₂Al mit CuAl₂-Struktur nachgewiesen; die Parameter sind:a=6,840 bzw. 6,76₂ undc=5,49₀ bzw. 5,37₄ kX·E. In den Dreistoffen: Zr–Al–Si und Hf–Al–Si besteht jeweils ein lückenloser Übergang zwischen den isotypen Phasen Zr₂Al und Zr₂Si bzw. Hf₂Al und Hf₂Si.     

Die Kristallstruktur von LiEu3O4

The crystal structure of LiEu₃O₄ which represents a new structure type was solved by usual methods with the aid of integrated WEISSENBERG photographs (MoK_α radiation, 787 reflexions) and refined to a reliability index of 4.3%. In LiEu₃O₄ just as in the first known europium(II, III)-oxide, Eu₃O₄, a clear distinction is possible between the divalent and trivalent europium ions. The given assignment which is based on crystal chemical arguments has been verified indirectly by means of the isostructural compound LiSr₂EuO₄, the cation distribution of which was established experimentally. The structure of LiEu₃O₄ is discussed in connection with the related oxides EuO and Eu₃O₄. The geometrical relations to the latter are of special interest, as LiEu₃O₄ undergoes a topotactical transformation into Eu₃O₄ by heating it in a high vacuum. There is an astonishing close structural relationship between LiEu₃O₄ and Yb₃S₄: except for lithium all the atoms are correlated as for isostructural compounds.     

Die Kristallstruktur von Ag3Co(CN)6

The crystal structure of the hexagonal Ag₃Co(CN)₆ (a = 7.03 Å, c = 7.13 Å, Z = 1) has been determined by X-ray powder methods. The structure factor calculations based on the space group D lead to a reliability index R of 0.062, the R̃-value from F²-sums of systematically coinciding reflections being 0.064. The cobalt atoms are located in the position 1 a (0,0,0), the silver atoms in 3g (1/2,0,1/2;0,1/2,1/2;1/2,1/2,1/2). The carbon and nitrogen atoms occupy the position 6k. The interatomic distance are: Co-C = 1.89 Å, C-N = 1.14 Å, Ag-N = 2.06 Å. The angle C-N-Ag is 157.3º.     

Die Kristallstruktur von Ru2Ge3

The crystal structure of Ru₂Ge₃ has been determined and refined by Fourier synthesis using pseudo-tetragonal X-ray data resulting from twinned crystals. The true symmetry is orthorhombic with space group Pnca-D _2h ¹⁴ and the lattice parameters are:a=5.718,b=11.436 andc-9.240 Å. Ru₂Ge₃ is a member of the Mn₁₁Si₁₉ structure family which is characterized by the occurrence of different compositions in the rangeTB _2?x (x≤0.75,T=transition metal andB=group III or IV metal). The compounds Ru₂Si₃, Os₂Si₃, Os₂Ge₃, and Ir₂(Ga_0.6Ge_0.4)₃ are isostructural.     

Die Kristallstruktur von Li2SnO3

Li₂SnO₃ crystallises monoclinic, C, with a = 5.295, b = 9.184, c = 10.032 Å and β = 100.13°; Z = 8. The positions of Sn were obtained from PATTERSON maps and the positions of O and Li by FOURIER difference method. Parameters were refined by least squares-method [1462 reflexes (h 01)–(h 71); R = 10.5%]. The average distances of Li? O are 2.07 Å, and 2.20 Å for Sn? O. The Li₂SnO₃ structure can be derived from the NaCl type: in a cubic closest packing of oxygen 2/3 of the octahedral holes are occupied by lithium and 1/3 by tin.     

Die Kristallstruktur von Ru2Si3

The crystal structure of Ru₂Si₃ has been refined by leastsquares using three-dimensional X-ray data from a twinned crystal (1355 reflections,R=5.8%). Ru₂Si₃ is isostructural with Ru₂Ge₃ and like this compound a member of the Mn₁₁Si₁₉ structure family. The lattice parameters of the orthorhombic unit cell (Pnca—D ₁₄ ^2h ) are:a=5.530 (1),b=11.060 (2) andc=8.952 (2) Å.

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Mit 1 Abbildung     

Die Kristallstruktur von V2PC und V5P3N

Ohne Zusammenfassung     

Die Kristallstruktur von H3Co(CN)6

The crystal structure of the hexagonal H₃Co(CN)₆ (a = 6.43 Å, c = 5.70 Å, Z = 1) has been determined by X-ray powder methods. The space group is D (at least pseudo), the cobalt atoms being in (0, 0, 0). Structure factor calculations lead to a final R-value of 13.2%, based on F²-sums of coinciding reflections. The carbon and nitrogen atoms are located at the vertices of a slightly distorted octahedron around the cobalt atom; the angle Co? C? N is 177°. The interatomic distances are: Co? C = 1.89 Å, Co? N = 2,98 Å, C? N = 1.09 Å. The pseudo-octahedral units of Co(CN)₆ are linked together by N? H? N bridges. Infrared spectra show that the most probable linkage is the one with a N? H? N-bond length of 2.7 Å.     

Die Kristallstruktur von Li2TeO3

Crystal Structure of Li₂TeO₃ Crystals of Li₂TeO₃ were prepared from melts. Li₂TeO₃ crystallizes in the monoclinic system, space group C2/c. The lattice parameters are a = 5.06₉, b = 9.56₆, c = 13.72₇ Å, β = 95.4°. The formular unit is 8. The crystal structure has been determined by Patterson and threedimensional differential Fourier synthesis refined by least squares using isotropic temperature corrections. The final R-value of 772 observed reflections is 0.101. Li₂TeO₃ forms a layer lattice consisting of trigonal TeO₃ pyramids and deformed LiO₄ tetrahedrons. The TeO₃ pyramids are only connected with the corners of LiO₄ groups, which are linked one with another by common corners and edges.     

Die Kristallstruktur von Ti3GeC2

Ohne Zusammenfassung     

Die Kristallstruktur von Li2GeO3

Zusammenfassung Die Kristallstruktur von Li₂GeO₃ wird mit Hilfe dreidimensionalerFourier-Synthesen und nach der Methode der kleinsten Quadrate bestimmt. Li₂GeO₃ ist isotyp mit Li₂SiO₃ und enthält [GeO₃]^2–-Ketten (Zweiereinfachkette). Die Gitterparameter der rhombischen Elementarzelle (C _2v ¹² –Cmc2₁) betragen:a=9,63₀,b=5,46₅ undc=4,85₀ Å. Als mittlere interatomare Abstände wurden erhalten: Ge–O=1,74 und Li–O=2,01 Å.

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The crystal structure of Li₂GeO₃ has been determined by means of 3-dimensional Fourier syntheses and least-squares method. Li₂GeO₃ is isostructural with Li₂SiO₃, containing [GeO₃]^2–-chains (Zweiereinfachkette). The lattice parameters of the orthorhombic cell (C _2v ¹² –Cmc2₁) are:a=9,63₀;b=5,46₅ andc=4,85₀ Å. The average interatomic distances are found to be: Ge–O=1,74 and Li–O=2,01 Å.

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Mit 3 Abbildungen     

Die Kristallstruktur von U2Cr3Si,U4Mn5Si3 und U2Co3Si

Zusammenfassung In den Dreistoffen: Uran–T (Ti,V,Cr,Mn,Co,Nb,W)–{Si,Al} werden Legierungen auf dem Schnitt U(T,Si)₂ bzw. U(T,Al)₂ aus den Komponenten hergestellt und röntgenographisch identifiziert^*. Es bestehen die ternären Verbindungen U₂Cr₃Si, U₄Mn₅Si₃ und U₂Co₃Si, die sich als mit MgZn₂ isotyp erweisen.     

Die Kristallstruktur von Fe12Zr2P7

Zusammenfassung Die Struktur einer ternären Phase im System Fe–Zr–P wurde mit Hilfe von Einkristallaufnahmen bestimmt und verfeinert. Die Kristallart entspricht der vonVogel undDobbener aufgefundenen Phase Fe₄ZrP₂ und hat eine Idealzusammensetzung von Fe₁₂Zr₂P₇. Die Gitterparameter der hexagonalen Kristallart sinda=9,0002 undc=3,5920 Å, die Raumgruppe ist . Die Struktur ist mit jener von Fe₂P verwandt.

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The crystal structure of a ternary phase in the system Fe–Zr–P has been determined and refined by means of singlecrystal X-ray methods. The phase, already described byVogel andDobbener as Fe₄ZrP₂, has the ideal composition Fe₁₂Zr₂P₇. The cell dimensions are found to be:a=9,0002 andc=3,5920 Å, the space group is . The crystal structure of Fe₁₂Zr₂P₇ is related to Fe₂P.

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Die Kristallstruktur von BaTeO3

Crystal Structure of BaTeO₃ Crystals of BaTeO₃ were prepared from melts. BaTeO₃ is isotropic with KClO₃ and crystallizes in the monoclinic system, space group P2₁/m. The lattice parameters are a = 4.63₃, b = 5.95₂, c = 7.30₈ Å, β = 111.2°. The formula unit is 2. The crystal structure was determined by Patterson synthesis, refined by least squares and confirmed by (F_o — F_c) synthesis. Using isotropic temperature corrections the R-value of 1072 observed reflections calculated as 0.748, and anisotropic the R-value as 0.702. In BaTeO₃ tellurium forms with three oxygen atoms pyramidal TeO₃-groups, barium has to oxygen atoms the coordination 7+2. The TeO₃ groups are not linked one with another, but with the BaO₉ polyhedrons by common corners and edges, the latter are linked one with another only by common edges.     

Die Kristallstruktur von ThGa2 und RuIn3

Zusammenfassung Im System: Th-Ga wird die Phase ThGa₂ mit -ThSi₂-Typ aufgefunden, im System: Ru-In werden die Phasen RuIn₃ mit CoGa₃-Struktur sowie eine Ru-reiche Phase mit hexagonal dichter Packung machgewiesen.Herrn Professor Dr.Erich Hayek zum 60. Geburtstag.     

Die Kristallstruktur von α-CaCr2O4

The Crystal Structure of α-CaCr₂O₄ Single crystals of the high temperature modifikation α-CaCr₂O₄ were investigated by X-Ray goniometer data. (a = 11.059, b = 5.836, c = 5.114 Å, space group D–Pmmn). α-CaCr₂O₄ is isotypic with SrCr₂O₄.     

Die Kristallstruktur von AlI3 2 Pl3: ein P2I5+ AlI4−

Crystal Structure of AlI₃ · 2 PI₃:P₂I₅⁺ AlI₄^? The crystal structure of the title compound was determined from single crystal X-ray data. P₂I₅⁺AlI₄^? crystallizes in the orthorhombic space group Pbca, a = 1 088.3, b = 1 827.3, c = 2 031.6 pm, V = 4040 · 10⁶ pm³, Z = 8. The P₂I₅⁺ and AlI₄^? ions are connected by weak iodine-iodine bonds (I? I distances between 343.5 and 376.3 pm). The mean P? I and Al? I bond lengths were found to be 240.9 and 252.9 pm respectively.     

Die Kristallstruktur von Li4SiO4

Zusammenfassung Die Kristallstruktur des Lithiumorthosilicats wurde mittels dreidimensionaler Fourier-Synthesen und nach der Methode der kleinsten Quadrate bestimmt. Die Gitterparameter der monoklinen Elementarzelle (C _2h ² –P2₁/m) betragen:a=5,14;b=6,10;c=5,30 Å und =90,5°. Die Struktur enthält isolierte [SiO₄]-Tetraeder, welche durch [LiO _n ]-Polyeder (n=4, 5, 6) verknüpft sind. Hervorzuheben ist, daß sämtliche Lithiumlagen nur partiell besetzt sind. Als mittlerer Si–O-Abstand wurde 1,632 Å erhalten; als Mittelwerte der Li–O-Abstände für die verschiedenen Koordinationszahlen ergeben sich: 1,975 [4]; 2,099 [5] und 2,247 [6] Å.

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The crystal structure of lithium orthosilicate has been determined by means of three-dimensional Fourier syntheses and the least squares method. The lattice parameters of the monoclinic unit cell (P2₁/m–C _2h ² ) are:a=5.14;b=6.10;c=5.30 Å and =90.5°. The crystal structure contains isolated [SiO₄]-tetrahedra being connected by [LiO _n ]-polyhedra (n=4, 5, 6). The positions of the lithium atoms are partially occupied only. The average interatomic Si–O distance is found to be 1.632 Å. The averaged values for Li–O distances given for the different coordination numbers are: 1.975 [4]; 2.099 [5] and 2.247 [6] Å.

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Mit 4 Abbildungen     

Die Kristallstruktur von Ce4As3 und Pr4As3

Ohne Zusammenfassung