Die Kristallstruktur von Mo2FeB2

Zusammenfassung Mo₂FeB₂ wird aus den Elementen synthetisiert. Diese Phase ist mit U₃Si₂ isotyp, jedoch mit Ordnung der Mo- und Fe-Atome.     

Die Kristallstruktur von (AsPh4)2[W2NCl10]

Crystal Structure of (AsPh₄)₂[W₂NCl₁₀] The title compound is formed by a slow reaction of AsPh₄[WNCl₄] in acetonitrile solution in form of dark brown crystals. The crystal structure was solved by X-ray diffraction methods (R = 4.7%; 1461 observed, independent reflexions). (AsPh₄)₂[W₂NCl₁₀] crystallizes in the monoclinic space group P2₁/n with two formula units per unit cell. The structure consists of AsPh₄^θ and [W₂NCl₁₀]^2θ ions. The tungsten atoms with oxidation numbers five and six respectively, are linked by a linear, asymmetric nitrido bridge (r WN = 171 and 203 pm). The trans-effect of the W? N-multiple bonds causes a significant difference between axial (W? Cl_ax 243 pm) and equatorial (mean W? Cl_eq 230 pm) bond lengths.     

Die Kristallstruktur von W2CoB2 und isotypen Phasen

Zusammenfassung Die Phasen Mo₂CoB₂, Mo₂NiB₂, W₂FeB₂, W₂CoB₂ und W₂NiB₂ kristallisieren in einem neuen Typ (W₂CoB₂-Struktur). Die Zelle ist orthorhombisch, die Raumgruppe D _2h ²⁵ -I mmm. Die Punktlagen sind 4 W in 4 f), 2 Co in 2 a) und 4 B in 4 h). Die strukturellen Bauelemente werden mit jenen von Mo₂FeB₂ (U₃Si₂-Typ) verglichen.

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The ternary compounds Mo₂CoB₂, Mo₂NiB₂, W₂FeB₂, W₂CoB₂ and W₂NiB₂ crystallize with a new type (W₂CoB₂-structure). The elementary cell is orthorhombic, the space group being D _2h ²⁵ -I mmmm. The atomic positions are determined to be 4 W in 4 f), 2 Co in 2 a) and 4 B in 4 h). Both crystal structures W₂CoB₂ and Mo₂FeB₂ (U₃Si₂-type) are compared with respect to the trigonal prismatic surrounding of the boron atoms.

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Mit 1 Abbildung     

Die Kristallstruktur von Berylliumamid,Be(NH2)2

Inhaltsübersicht. Die röntgenographische Untersuchung von Einkristallen des Beryllium-amids ergab, daß die Verbindung tetragonal kristallisiert. a = 10.170 ± 0.005 Å. c = 16,137 ± 0,008 Å und c/a = 1,587, in der Raumgruppe I4₁/acd mit 32 Formeleinheiten in der Elementarzelle. Es wurden die Lagen aller Atome einschließlich derer des Wasserstoffs bestimmt. Die Struktur des Be(NH₂)₂ leitet sich von einem stark verzerrten, kubisch dichten Anionenteilgitter ab. Die Kationen befinden sich derart in Tetraederlürken. daß jeweils 4 Be²⁺-Ionen ein regulärs Tetraeder mit den kürzesten Be — Be-Abständen bilden. Dadurch entstehen Einheiten, die sich als Be₄(NH₂)₆(NH₂)_4/2 wiedergeben lassen, wobei die äußeren 4 Amidionen als Brückenanionen für die dreidimensionale Verknüpfung wirken. Die Ausrichtung der Amidionen wird beschrieben und mit den Ergebnissen früherer Untersuchungen an venvandten Metallamiden verglichen. Crystal Structure of Beryllium Amide, Be(NH₂)₂ Abstract. The x-ray investigation of single crystals of beryllium amide led to the following results. The compound crystallizes tetragonally a = 10.170 ± 0.005 Å, c = 16.137 ± 0.008 Å, and c/a = 1.587. The space group is I4₁/acd. The lattice contains 32 formula units. The positions of all atoms including hydrogen were determined. The structure of Be(NH₂)₂ can be described by a strongly deformed cubic closepacking of anions. The cations occupy tetrahedral interstices so that 4 Be²⁺ ions form a regular tetrahedron with the shortest Be—Be distances. This causes units, which can be described by Be₄(NH₂)₆(NH₂)_4/2 Whereas the outer 4 amide ions serve as bridging anions to give a threedimensional arrangement. The orientation of the amide ions is given and compared with earlier results on similar metal amides.     

Die Kristallstruktur von Zr(Sn,Sb)2

Ohne Zusammenfassung     

Die Kristallstruktur von Bariumamid,Ba(NH2)2

The Crystal Structure of Barium Amide, Ba(NH₂)₂ Single crystals of barium amide can be obtained by the reaction of barium metal with ammonia during long times. At ? 70° C Ba reacts with the solvent very slowly. The resulting amide then is well crystallized. Crystals can also be grown at 125° C in a temperature grakient. In both cases 3 to 4 months are necessary to get crystals of about 0.1 mm in diameter. Barium amide is monoclinic a = 8.951 Å, b = 12.67 Å, c = 7.037 Å, und β = 123.5° with 8 formula units. The space group is Cc. All atoms occupy the general position. The structure of Ba(NH₂)₂ shows two different Ba atoms with respect to their surrounding. One of them is coordinated irregularly by 8 amide ions, the other by 7 amide ions. The nitrogen atoms have 11 neighbours to each other. This means, that they are relatively close packed. Barium amide has a coorkination type structure, whereas the low symmetry of the arrangement of the different ions may be explained by the dipole chracter of the anion, and by packing effects.     

Die Kristallstruktur von PrTe2

The Crystal Structure of PrTe₂ X‐ray diffraction single‐crystal structure analysis of PrTe₂ prepared by chemical vapour transport reactions starting with praseodymium and tellurium in the presence of trace amounts of iodine also revealed superstructure reflections indicating just as for CeTe₂ a (2 × 2 × 2)‐supercell of the basic anti‐Fe₂As‐type structure instead of a (2 × 2 × 1)‐supercell as for LaTe₂. In contrast to LaTe₂ with monoclinic symmetry (space group P1c1), PrTe₂ crystallizes tetragonal in the space group P4 with the lattice parameters a = 896.80(5) pm and c = 1811.9(1) pm (Z = 16). The doubling of the c‐lattice parameter compared to LaTe₂ is observed due to different polyanionic structural motifs in the heights z ≈ 0 and z ≈ ¹/₂. These are a herringbone pattern of [Te₂] dumbbell pairs (motif A; a topology which is also found in LaTe₂), isolated square four‐membered [Te₄] rings in z ≈ 0 (motif B) and additionally rectangular four‐membered [Te₄] rings in z ≈ ¹/₂ (motif C). Though CeTe₂ and PrTe₂ are crystallizing isotypically, there are distinct differences in the interatomic distances within the polyanionic Te layers and resulting from these also a different topology of the structural motif C. The individual structural elements are causing a diffraction pattern, which is all in all to be explained by a statistical superposition of the different elements in form of microdomains.     

Die Kristallstruktur von NaBiO2

The crystal structure of NaBiO₂ NaBiO₂ crystallizes monoclinic in C with a = 7.39₄, b = 7.26₂, c = 5.88₆ Å, β = 127.7°; Z = 4. Parameters were refined by least-squares (555 hkl with |h?l| = 0 to 4; R = 10.9%). Angular groups [BiO₂] are twisted by 180°, forming chains [BiO_2/2O_2/2] along [001]. The MADELUNG part of lattice energy (MAPLE) is calculated and discussed.     

Die Kristallstruktur von Ag2TeO2(OH)4

Zusammenfassung Die Kristallstruktur von Ag₂TeO₂(OH)₄ wurde mit Hilfe von Einkristallmethoden bestimmt und nach der Methode der kleinsten Quadrate verfeinert. Die Gitterparameter der Elementarzelle (Fdd 2–C _2v ¹⁹ ) betragen:a=18,72;b=6,48;c=8,94 Å. Mit allen beobachteten Reflexen wurde einR-Wert von 8,50%, unter Einschluß derHamilton-Reflexe einR-Wert von 9,41% erhalten. Die Telluratome sind oktaedrisch von 6 Sauerstoffen umgeben, während die Silberatome stark verzerrt tetraedrisch von 4 Sauerstoffen umgeben sind. Zwei dieser Tetraeder bilden mit einem dazwischenliegenden Oktaeder eine geometrische Einheit. Diese Einheiten sind über Sauerstoffe, die zu zwei verschiedenen Tetraedern gehören, und über Wasserstoffbrücken zu einem dreidimensionalen Gerüst verknüpft.

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The crystal structure of Ag₂TeO₂(OH)₄

The crystal structure of Ag₂TeO₂(OH)₄ has been determined by single crystal X-ray methods and refined by the least squares method. The lattice parameters of the cell (Fdd 2–C _2v ¹⁹ ) are:a=18.72;b=6.48;c=8.94 Å. With all observed reflections anR-Value of 8.50% was obtained; if allHamilton-reflections are includedR=9.41%. The Te atoms are surrounded octahedrally by 6 oxygens, the 4 oxygens around the silver atoms form a distorted tetrahedron. Two of these tetrahedra form with an intermediate octahedron a geometric unit. These units are linked together to a three-dimensional structure by oxygens belonging to two different tetrahedra and by hydrogen bondings.

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Mit 5 Abbildungen     

Die Kristallstruktur von RhHg2

Zusammenfassung RhHg₂ kristallisiert tetragonal mita=4,55₁ Å,c=2,99₈ Å,c/a=0.658₈ in der Raumgruppe P 4/mmm. Die Phase ist isotyp mit -PtHg₂.

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The structure of RhHg₂ was found to be tetragonal; the unit cell ofa=4,55₁ Å,c=2,99₈ Å,c/a=0,658₈ belongs to the space group P 4/mmm. RhHg₂ is isostructural with -PtHg₂.

     

Die Kristallstruktur von TaNi2

Zusammenfassung TaNi₂ kristallisiert im MoSi₂-Typ.     

Die Kristallstruktur von In(CH2Ph)3

Crystal Structure of In(CH₂Ph)₃ The reaction of InCl₃ with PhCH₂MgCl forms tribenzylindane 1 , precipitating from toluene as pale yellow crystals. The crystal structure shows one dimensional chains of 1 in a zigzag arrangement. The synthesis and characterization of (PhCH₂)₂InCl 2 and PhCH₂InCl₂ 3 is reported.     

Die Kristallstruktur von LiInSe2

The Crystal Structure of LiInSe₂ The crystal structure of LiInSe₂ has been determined from single crystal data (β-NaFeO₂ type, space group Pna2₁ (No. 33), a = 718.3(2), b = 839,8(3), c = 678.1(2) pm; 375 hkl, R = 0.032; R(w) = 0.029). The mean values 253.6 pm of the bond distances Li? Se are larger than calculated, the distances In? Se (256.8 pm) are equal with the calculated values. The structure is discussed in relation to the analogous LiB^IIIC₂^VI compounds.     

Zur Kristallstruktur von W2C

Ohne ZusammenfassungMit 1 Abbildung     

Die Kristallstruktur von V2C

Zusammenfassung V₂C kristallisiert je nach Art der Entstehung in einer orthorhombischen Form (-Fe₂N-Typ) oder mit der bekannten hexagonalen Struktur.

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The subcarbide V₂C crystallizes with an orthorhombic cell (-Fe₂N) as well as with the known hexagonal cell depending on the mode of formation.

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Mit 2 Abbildungen     

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 Ta2Be

Zusammenfassung Die Phase Ta₂Be wird aus den pulverförmigen Komponenten durch Sintern bei 1300°C hergestellt; sie kristallisiert im CuAl₂-Typ.

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Ta₂Be has been prepared by sintering of the components at 1300°C. The crystal structure of Ta₂Be has been found to be isotypic with CuAl₂.

     

Die Kristallstruktur von Mo2BC

Zusammenfassung Die Kristallstruktur von Mo₂BC wird ermittelt. Die Elementarzelle ist orthorhombisch und enthält vier Formeleinheiten. Die Umgebung des Bor-bzw. Kohlenstoffatoms entspricht einerseits dem Monoboridtyp und andererseits den kubischen Monocarbidstrukturen.Mit 1 Abbildung     

Reaktionen von Diorganogallium(indium)fluoriden. Die Kristallstruktur von Mes2InF

Reaction of Diorganogallium(indium) Fluorides. The Crystal Structure of Mes₂InF Mes₂GaF ( 1 ) reacts with t-BuNH₂ at 20°C to the amine adduct [Mes₂Ga(F)(t-BuNH₂)] ( 2 ). Treatment of 1 with H₂S gives after a redox reaction γ-S₈-Sulfur (Muthmanns' Sulfur) ( 3 ) as the only isolated product. When i-Pr₂InF ( 4 ) is reacted with [SnCl₂(dioxane)] in toluene at 70°C one yields after workup [i-PrInCl₂(dioxane)] ( 5 ), which is formed after ligand exchange and reaction with dioxane. 2 and 5 were investigated by NMR-, IR- and MS-techniques. In addition, 2 · 2,5 THF, 3, 5 and Mes₂InF were characterized by an X-ray structure determination. According to that 2 · 2,5 THF contains dimeres, associated by hydrogen brigdes, while 5 possesses a polymeric structure with bridging dioxane molecules. 3 forms eightmembered rings with C ₂-symmetry. Me₂InF is a trimer in the solid state with an In₃F₃-backbone.